There is a plethora (isn't that a great word?) of great advice here for writers. I love Richard Ford's advice the best.
If I were to add something it would be : get yourself a decent chair with good back support to write in. Not glamorous advice, but practical and you'll thank me one day. Or you'll give all your royalities to a chiropractor and say, "I wish I'd listened to Lori when she told me..."