The best thing you can do for your craft is to close the door. This may be a literal door, signing off of IM, closing your email client, or pulling out your internet cable. It may also be metaphoric, especially once you have practiced enough. It is concentrating your focus so severly on what you are doing that nothing else matters. I have received this advice from much of my reading, and from some very successful people. Don't believe me, who the hell am I? Just try it, try for 5 days, try for 3 hours. Look at the results and honestly compare to your other work. Practice closing the door.