Excellent blog from Robert Repino in OUP about writing a novel – basically he says write short stories for 6-12 months before you think about moving on to longer projects.
Also from OUP, tips for being a better writer.
And, just for fun I did the ‘what sort of writer are you?’ quiz on the OUP site. Flatteringly the answer I got was Hemingway, with Raymond carver and George Orwell as alternative possibilities. Oh well, I can only hope…!