I'd reccomend anyone interesting in writing for a living, look at Hunter S Thompson's letters, The Lost Highway. Covers his early period, including the time he spent in Puerto Rico which became the Rum Diary. It gives a good perspective on what has just been said - was it Einstein who said "Genius is 1% inspiration, 99% perspiration". You can't expect everything you write to be good, so write as much as possible, it increases your chances.
I also think an important part of writing that some people don't grasp is READING. A writer should always have in mind their reader - I'm not suggesting bowing down to commericialism or anything like that, but you really should write something you would want to read...
To become an artist you need to know the rules first, then you can break them. Read, practice writing and find your unique voice. Don't try to be someone else and for gods sakes avoid cliche. How many 'first novels' do you think are sitting in drawers all over the world which are about a writer struggling to write a first novel...
