Ten rules for writing fiction, from many authors (and here's part two). I met Gareth W. this morning who recommended these, and he's picked out some favourites. Worth a read! In particular, he pointed me at this one:
Write every day. That way, the book you're working on is never out of your awareness for long. It will always be percolating in the back of your mind, growing on its own. No part of writing is as hard as getting the engine warmed up, so try not to let it cool down. Amen.