So Back on topic:
1. There is no perfect camera. So learn to frame with what you have, and let go of that perfect frame that your perfect imaginary camera can capture.
Yes, no matter how sophisticated the camera, they have yet to invent one with an inbuilt 'interest' meter that can tell you where to point it!
An interesting, photo can be forgiven a multitude of sins, provided some-one WANTS to look at it. Perfectly composed, perfectly exposed, photo can be perfectly boring and not interest any-one.
Always ask yourself WHO will want to look at the picture you are making, and then ask WHY they will want to look at it. Answer maybe that only you will ever want to look at it, and for no other reason than you took it... but even those answers start to give direction and purpose to your photography.
A photo should have a purpose. Without a purpose its just a bit of scrap paper, (or wasted bytes!) People should want to see a photo. Either because it entertains or it informs.
99% of photo's probably dont do either (and most, ironically, by people who would consider themselves keen photographers!). they are mere snap-shots of something that caught the photographers eye at the time, and after the event have no interest to inform or entertain even the person who took it!
Ask Who and Why, and give your pictures some meaning. Dont waste film or bytes making rubbish.
Apply that rule, and even fundamental basics such as cocking up focus, let alone being off on composition, or being out on exposure, dont matter so much. You at least have a photo that has a reason for being..... its then merely a case of making 'better' photo's with a reason for being... a photo that has no reason for being looked at, wont be looked at, regardless of how artfully its composed, how wonderfully exposed, or how high the image quality gained might be!
Choose one camera and stick to it. The mind can then focus on composition. Most film cameras have the same basic features, and certainly exceptionally high quality primes. Any will do.
I'm not so sure of this advice. It's certainly an advantage to be familiar with your kit, and ultimately, the camera itself and how 'good' a camera it may be is not particularly significant to how good a photo you can get out of it, but?
Fixed lens range-finders and compacts, particularly more antique ones can be very limiting. You suggest sticking to a single lens, and these would enforce that 'discipline', but like as not also bring other restrictions, such as limited 'zone' focusing, or automatic only exposure control, or limited range of manual control.
Sticking to such a camera then can force you to think more about what control you have, in order to exploit it, can be informative to instilling good in camera discipline, but can also be frustrating when you want or need to push the envelope of operation, and expand repertoire of subjects.
eg: my little Olympus XA2 compact with fixed 35mm wide angle lens is a great camera, and brilliant for landscapes and snap-shots; but with zone focusing, and only the ASA selection scale to offer exposure compensation; I couldn't take nice selective focus, wide aperture portraits very easily; action photography was rather hit and miss on what shutter speed the program chose, and for motor-sport, umpety meters behind spectator safety, I'd never get frame filling action.
SLR's with more manual control, and the possibility of interchangeable lenses for different situations, really opens up the opportunities, if you wish to explore them. But at the same time, gives a lot more room for error using them wrongly.
Meanwhile, sticking to a single camera, can stifle your photography, encouraging you to do the same thing, the same way, and keep taking the same 'rubbish' photo's over and over again, merely improving the technical merit of that rubbish, not make it more interesting or worth while!
After starting a C&G course in Photography, I think about four years into my own enthusiasm for SLR photography, and at the time, utterly broke... I discovered an old WWII Voiglander twin-lens reflex camera in an attic.... and started a little adventure into antique cameras, I started collecting when people had clear-outs.
Running a roll of film through that camera, and having to use a waste level view-finder, with the reversed framing view! WOW! Complete mind melt!
First of all, to compose a shot, I had to hold the camera three foot lower than I did a conventional SLR or range-finder compact! WHAT a completely different perspective! Taught me something that; DONT just stand there and stick camera to face and press the button. Crouch down, LOOK at the subject from all angles. aided by fact that moving the wrong way in the view-finder, I had to be hyper aware of what was going on in the corners of the view-screen to keep it all in frame!
Another was an old bellows 120 roll film Press-Camera. No view-finder... It had a wire composition guide! And I think only about three shutter speeds and maybe four apertures, as well as having to meter manually or guestimate exposure, not rely on TTL metering. More lessons learned, new techniques, independent metering, and backing up, getting a wider shot, and giving yourself room to compose by cropping, as well as working to hyper focal distances and giving latitude to depth of focus to compensate for having absolutely no way of seeing what the Depth of field might be in the camera.
Using different cameras, learning their foibles, CAN be informative, and give you new perspective on your photography, encouraging, if not forcing you to try new techniques you might never other wise consider.
2. Use one prime for a long period. 50 mm is a good one. That will force you to learn of the compromises you need to make to get a good shot. Photographs stand and fall on composition, not on the technicality
See above. No.. they dont even stand or fall on composition. They stand or fall on INTEREST and whether there is anything in the picture a viewer actually wants to see, that informs or amuses them. Composition is just the first step to making it 'nicer' to look at for them.
See above. No... limiting yourself to a single prime lens, is not necessarily a great way to go. Yes, it helps make you think about composition, but at the same time, denies a lot of the versatility you may have with a camera, denying opportunities, as well as potentially encouraging you to merely keep doing the same thing, over and over again, NOT actually learning anything new.
3. Not everyone likes darkroom. I certainly dont. But thats not a problem- HCB didnt, so we are in good company.
I have no idea whether Henri Cartier-Bresson was in fact 'good company'; I never dined with the chap. But the idea of spending an evening in a room full of his acolytes, hailing him as the peerless svengali of all photography, would have me reaching for the razor blades! 
It's back to the matter of the tools at our disposal and whether we choose to utilise them or not, as limiting yourself to a single camera or a single prime lens.
The dark-room, conventional or digital, is another set of tools in which influence over the final picture a viewer may look at can be exerted. And its that final picture that matters at the end of the day. The thing some-one is going to look at, and hopefully, they have an interest at looking at.
Opportunities to tweak or correct mistakes made 'in camera' exist, as well as many other opportunities to alter or even make a completely new picture, that are almost impossible to do other wise, are possible IF you choose to exploit the tools available in this area of photography.
Understanding post-processing, choosing to exploit it, like any other photographic technique can be done for good and bad. But the camera is an imperfect tool. And when we take a photograph, we are creating a mere representation of what we viewed. There is no such thing as a perfectly undistorted image, apart from the one we see with out own eyes. And even in camera we exploit translation distortions to creative effect.
Eg. Selective focus. Its a feature of the lens & aparture that creates a shallow depth of field, that is not the scene we 'see'... but we are happy to exploit that 'distortion' even applaud it, in composition to focus attention on a subject.
What is the difference, then to using tilts in printing to 'correct' converging verticals? Is it more or less legitimate than using a tilt lenses? What about dodging and burning, to even exposure between highlights & shadows? Or using exposure merges or even montages?
The Dark-Room opens up a completely new set of possibilities and tools, to use or not use, to use well or badly, as you choose, and are no more or less 'righteous' than in camera techniques.
It is a contentious subject, for sure, and there is a lot of merit to the philosophy of clean camera work, and not relying on post-processing. BUT, post processing can offer an awful lot to your photography, and accepting, nay grasping post-processing, can inform your in camera work; open up completely new opportunities and direct your in camera technique in completely new ways to take in-camera images specifically for post processing!
Eg; HDR... modern automated, and hugely over used automatic means of exposure merging. Pioneers in the days of low emulsion latitude were doing that in the dark room, taking two or three exposures for highlights, shadows and mid-tones and over-exposing them in the printing stage to get a full tonal range in print. Is this wrong? Should they have presented pictures with burned out highlights and blacked out shadow, because that was all their emulsion could capture? Is the modern photographer, using wide range film emulsion in some-way better getting their picture in one go in camera? Or are both exploiting the tools and techniques at their disposal, with the skill they have acquired to achieve the same ends?
Montaging. Done to death in modern digi-dark-room, often very badly; cutting out granny from family snap and pasting her into a back-ground of the Taj-Mahal or whatever. Its a means of making an image, and again, was done in the days of the chemical dark-room, to create 'interesting' pictures. And IF you want to do it, and do it well, so that it looks natural, then it is incredibly hard, and can demand an awful lot of very careful photo planning, and designing photo's to shoot in camera to give you the various elements to merge, so that perspective shifts or lighting patterns dont 'glare' and make it look obviously false. Are such pictures wrong because the photographer used the full range of tools at his disposal, mixed with skill, dexterity and imagination to make something NOT created in camera? I suppose then Ruben was an importer, because he made pictures without even a camera!
4. Choose the best film you can afford. That is the key ingredient to good picture. You will learn how the film behaves under various lights. I mostly use Porta.
Yes... and no. I have to confess, that looking back over my archive of old negs, that I REALLY wish I could have afforded better film for so many shoots..... it IS probably the most influential ingredient a lot of the time on final Image Quality....
But yet again, to deny experimentation, to deny variation, or selecting different tools for different jobs, steers you not to learn, but to repetition.
I used high speed film for action or low-light photography; I used slow speed film for landscapes and still life. I used colour print film, I used slide film, I shot black and white. I used expensive Fuji and cheap Croatian Konica copy film... probably most often, as it was what I could afford, to keep the camera loaded. May be didn't get the best image quality I might, but I got pictures.
And films respond differently. Using a variety of stock you get to know which work better in what situations, and like selecting lenses or even cameras, you can learn to exploit better film for the situation, or not waste 'good' film where its not needed.
Back to tools for the job, and recognising opportunity and exploiting it to advantage. Not denying opportunity for some misguided idea of discipline.
5. Choose one pro lab and stick to them. Make friends with the operator, and explain to the operator how you see a shot. He will de able to print better. I use club 35
In an ideal world... maybe... But for film processing, these days its often Hobsons choice. Yes great if you have a one man, one machine lab, where that one man and one machine ensures consistency between films... but other wise? As likely as not pot luck, and consistency cannot be totally assured. Modern electronically metered mini-labs though, generally offer a reasonable level of consistency, and not just between films or batches on one machine, but between machines, even in different labs.
So unless you are a diligent DIY Dark-Roomer, assuring your own processing consistency, you either pay top dollar for pro-service and hope for the best, or bung it in on budget to whatever mini-lab or postal processors you can afford.... and the consistency and quality assurance is all within industry standards of 'acceptable quality limits', while chances of a rogue effup, tearing your negs or creaming your emulsion, or bluing your prints, probably aren't much different who ever you use! You are just more likely to get re-immersed the film price rather than shrugged shoulders when you complain to a more expensive service!
6. Use slide films often. It will show how the photo actually came out without any intervention at the print stage.
True... but.... why should this be important?
What matters is the final image presented to the viewer.
How you get it there, is up to you. Comment really reveals more about your inclination towards in-camera clendliness, and distain of post-processing than anything.
It is a good tool for instilling good in camera discipline, but as comments so far; photography is not all about good in camera discipline, its about making pictures people want to look at. Remember the objective, remember, ask WHO and ask WHY.
People dont generally want to look at slides; and even as a photographers own appraisal medium, HOW are you going to look at them? 35mm on a light-box? You aren't going to see very much in such a small artefact, are you? Even under a lupe. Projected on a screen? You are no longer looking at the first hand article, but a second generation image, subject to enlargement distortion and error.
You will almost NEVER view a 35mm frame in detail, you will always look at it in some second generation enlarged reproduction. Accept that, and the worth of using slide film to appraise how clean your camera work is rather diminished before you consider that is almost never going to be the finished 'Picture' for the viewer.
Yes, its good to know about and worth pondering for clean camera work; and clean camera discipline is useful. But it is only a very small part of getting image from camera to viewed picture.
Who and Why. The final picture people are going to see, on a computer screen, in a photo album, in a frame on some-ones wall, whatever THAT is the finished article the thing people are going to look at..... WHO is going to look at it? And WHY would they be interested?
7. Revisit old photographs. You will be surprised how much can be learnt from it
Well, possibly... but we're going round in circles. If, following some of your advice, you have been steered towards repetition; sticking to one camera, one lens, one brand of film, one photo-processors, one type of photography, and eschewed all opportunities to explore and experiment with your photography..... chances are, you have hundreds and hundreds of photo's that are ALL the same with little variation or variety and no progression showing any learning, that either confirm you are the great photographer you would like to be.... or disappoint, because nothing stands out as being very wonderful or at all different!
8. All photos are good photos, even the snapshots. They all have a place.
No.. they dont... well... OK.. maybe they do... the 'place' for many being the bin, or unseen in a dusty album some-where.
WHO and WHY. Photos have absolutely NO meaning, no relevance and no purpose unless some-one has some interest in it, and wants to look at it..
For some-one to want to look at a photo, it has to have some interest. It has to amuse, entertain or inform them in some way. It has to INTEREST them.
Blury snapshots of Auntie Mable loosing her knickers, can be forgiven all ills, because there is some interest to a viewer in them. Perfectly posed, perfectly composed, perfectly exposed and perfectly boring photo of something of little interest or relevance to any-one, except maybe the photographer, no-one will spare a moment to glance at.... that has little or no place and is a waste of film.
Theres a fair bit of wisdom contained in your advice; and there is an underlying philosophy struggling to get out of it, which is, Take Photos Learn From them
and a lot extolling the virtue of In-Camera-Discipline and keeping it clean in camera and not trying to make a silk purse out of a sows ear, correcting camera mistakes in post processing.
But theres also a lot of distortion and some perversion in there, that without understanding the wider context around the advice, without qualification, is unfortunately less helpful, and as suggested, would tend to steer a new photographer down a very stifling path, contrary to your aim, I am sure, sticking to arbitery constraints, not exploring all the potential creative avenues within the persuit of photography, persuing in camera cleanliness to the exclusion of all else, refining ever more perfectly boring photos showing ever more technical dexterity, and an utter absence of interest, experimentation, of appropriate use of available tools.
Nothing is photography is wrong
only how it is used. And what matters, ultimately is the picture people look at
. And whether there is any reason they would want to.
WHO is going to look at the photo you are taking
WHY will they want to look at it.
INTEREST is all.
Everything else is legitimate, and merely a means to an end.
however, trying new gear is part of the fun for me (although I obviously do occasionally try and produce a decent image or two!), but I definitely agree in terms of pure photography.
