You have basically asked "How to I become a better photographer" as a single question. It's impossible for one forum thread to tell you everything you need to know. Read a lot, practice a lot. Photography is inherently complicated and takes years of practice to be professional... assuming you mean professional the way I mean it. Professional, literally means someone who earns their way in photography, but to me it means someone who is expert technically, creative and innovative, and can handle any situation with ease and can produce the results asked of them repeatedly and reliably.
There's no way any one forum thread can do that for you... it takes years.
Start by reading a basic photography book.
http://www.amazon.co.uk/Basic-Photography-Michael-Langford/dp/0240515927
That would be a good place to start.
If you're impatient I've put a tutorial for the basics together
here.
If you were hoping for a quick fix solution, I'm afraid there isn't one.
If you're already fairly competent technically, then you need to just practice more. Set yourself projects.. push yourself out of your own comfort zone. Look for competition briefs and enter them a great deal. Read the specific threads on here... for example, if you want to know more about lighting, then read the lighting threads in here a lot.