Here are my thoughts I haven't commented on all the photos as some of them I couldn't spot any real errors nor was there anything that screamed brilliance at me. If any of my comment offend you or you don't agree with them please remember I know almost nothing about photography I'm only stating an opinion and I'm quite often wrong
(I'm told the being wrong thing isn't limited to photography either )
Anywho here we go
Letterbox
Nice idea spoiled slightly for me by the colour noise visable on the brass of the letter box
Chessboard
Again nice choice of subject but you should really have had the straight edge of the board level with your border its not off enough to look deliberate but enough so its easilly noticable I would have prefered to see a midgame shot as it were rather than the pieces in a neat line but that may just be me.
Bob the builder
I really like this image the OOF cat in the background ballances things nicely and the use of green material (felt?) as a pheudo grass works brilliantly
Fireplace
Nice fire you've got going there but for me everything seems to well lit, did you shoot this during the day? Did you try any shots using the fire as you primary source of light might have give more atmosphere?
Eggcup
Such a simple image that works really well if I were to be uber picky you've shaved a bit of the shadow off.
Flower
nice compsition I'm lead to believe it takes talent or an extereme amount of patience to photograph flowers (or should that be blooms?) well. I know nothing about flowers but to me on my monitor it looks a tad pale perhaps a touch more saturation?
Frog
Mine so can be truly nasty about it
I like the contrast of the light wooden "floor" to the dark wood of the frog. I don't like the nearest end of the stick being out of focus and the background is rubbish obviously added in photoshop with a nasty dark edge at the join should have had the light wood continue if possible
Tomatoe?
I think you had a great idea here which doesn't quite work for me because you've not got as close as I'd want. I think you should have only had one quarter/cell in full not being able to follow the cell wall around irritated me or rotate it slightly counter clockwise so the cross was square witht the frame
Spices
This one had me pondering for a while and in all honestly I can't tell you why I don't like it I should nice colour interesting lines but I don't sorry.
Ceramics?
for some reason my eyes head for the blank space between the subjects here instead of to them I think the candle holder? on the left is interesting enough to have been the sole subject
Dollhouse
Out of interest what did you do to this photo? was it photoshoped with a larger semi transparent layer or did you play with a long exposure and the zoom on your camera?
Darth maul
I could decide if the mp3 player lent interest to the photo or was a distration in the end I went with distraction apart from that you've done a brilliant jobI wish I could get my images as clear and punchy
Light
I've not got much to say about this one shot shot has been exposed brilliantly and I'd imagine a light to be unforgiving to small errors. I would have liked to see the whole elipse of the lamp rather than having it cut off at the frame
