I read an article, can't remember where, that mentioned focusing on what you CAN eat rather than what you CAN'T eat- planning is really important. This is hard at first, but it gets easier. I find if I don't think about what I'm going to eat ahead of time and make sure it's available, I end up eating crap.
I also weigh myself every day! I know a lot of people say don't do that because your weight fluctuates, it's depressing, etc, BUT it's not depressing if you're seeing the numbers go down every day. And if they're up a little, it makes me pay more attention to what I put in my mouth that day so that I can see a drop the next morning. If I'm not seeing a drop (or at least the same number) then I know I need to change something.
Good luck on Friday!