The best advice for anyone wanting to be a writer is, Write. Sure, read books, learn from others, keep a notebook, but it always comes down to just one thing: you and a blank page.
Here Elmore Leonard explains his rules for writing, in this rather hastily edited package from the BBC Culture Show of 2006. As Leonard explains writing is mainly rewriting, and it takes the pulp fiction maestro 4 pages of hard graft to produce one finished page. Now you know, so get cracking.