In the previous post I mentioned the first rule of writing goals: set word or page goals, not time goals. The second major rule is:
Keep moving forward!
No U-turns to keep going over and over what you've done already. Forge ahead until you've done a first draft, then go back and start to rewrite.
If you have ideas about rewriting that you're afraid you might forget, jot them down, then carry on.
(For more tips on writing, see my book, "Your Writing Coach," and the website at www.yourwritingcoach.com)