I've been on a diet for my wedding and here are some tips that have helped:
1. Counting calories. I keep a calendar on the fridge and write down every single thing I eat. It really helps when you reach for something, add it to the running total, and see how close you are to the daily limit you set yourself. It makes you think "is it really worth it?"
2. Sugar-free, low calorie things. Sweets are my downfall. 60 calorie puddings are very tasty. Sugar free jello is only 10 calories. Light yogurt is also great and they have a lot of chocolate/sweet flavored stuff. Diet pop is also good when you have a sweet tooth. The 90 calorie quaker mini delights are also delicious.
3. Gum. Whenever I have a sweet tooth and want to eat ANOTHER pudding or something, I pop in some gum. The calories are negligible and it helps the craving pass before you have more sweets.
4. Weekly weigh-ins. If there is a week you gain or don't lose weight, it will motivate you more during the next week to not cheat. It also keeps you accountable so things don't slip too much before it's too late. I wouldn't weigh yourself more than once a week though. If you start weighing daily then you get into the whole water-weight and daily fluctuations nonsense and it will just depress you.
5. Plan around indulgences. If you know you are going out to eat, don't eat until you go out. Once you start counting calories you will be amazed how horrible 99% of everything is (example, a cinnabon is almost 800 calories

That's like half your days calories right there). Again, when you go out to eat just think about whether something is really worth it. The restaurant or special food will always be there; you don't need it right now.
6. Join a gym. When you have spent the money you will be more motivated to actually go. Force yourself to work out or go the day after a bad eating day; you will feel less guilty.
7. Rice crackers. They have a lot of different flavors and it will satisfy salt cravings. Much better than eating chips. If you spread fat-free cream cheese on plain rice crackers it doesn't taste bad and it's only like 45-50 calories total.
That's all I can think of right now. Good luck!