I want to point out that I admire ChickieChick's conviction, but I do make mistakes from time to time.
I absolutely cannot let a mistake or a "could've been better" decision keep me from my goals.
You mentioned one month seemed to be about as long as you've stayed with your plans. I'm going to suggest a goal for you. Two months. Not to stay perfect for two months, mind you, but to focus on the days themselves.
So, if (not when, merely if), you end up eating a cheeseburger or whathaveyou at the end of the first month, you have something to keep you going forward. Your goal to still be making better choices at the end of month two.
~Made of star stuff~