Writing is a skill, and like all skills it must be practiced to improve. There's only so far exercises can take you, so one day you're going to have to sit down and write that first novel, or short story, or article. It will be crap to some degree.

As your skill grows and your writing matures and you develop your own style, your writing will improve. If you've been writing for a while, just look at something you wrote this month and something you wrote a year or more ago. I'll bet you've improved in that time.

There's a saying among some writers that states that every writer has an infinite supply of "good words" inside them, blocked by 100,000 "bad words" which must all be written out before the "good words" start flowing. Depending on who you talk to, the number of "bad words" can vary from 10,000 to 500,000, but the sentiment is the same. This is not, however, free license to write badly.

To "clear the queue" of these bad words you have to write the best you can, try to improve, study your own writing mercilessly to identify problems (this is best done some months after you last looked at the piece, ideally after you've improved your writing a bit) and be prepared to abandon the whole thing when necessary. You should take care to not throw it out in a moment of low spirits, though - wait until you're feeling better to decide. There may be salvageable parts that you can't see at the time.

Despite all this advice, the first novel is still very intimidating. There's the lure of the "famous first novel" table - see above. There's the desire to get it just right - see above. There's the feeling that this novel is your life's work - it isn't. There's the fear that you won't be able to think of any ideas for other novels - you will.

If you are a writer, you will write. Your life's work will be everything you write, not your first attempts at writing. Ideas come to those willing to see them.

So write, try to improve, and don't let your inevitable imperfections give you ulcers. Abandoning your first novel is allowed. I've done it twice to novels and I don't know how many times to short stories. I cringe to think of anybody finding my early work.