The thing that helps me the most is to not have any "bad" food in the house at all and make sure that you plan your next few meals so that you don't end up so hungry that you stop at McDonalds or somewhere. If I eat fast food, I go by Taco Bell and get something FRESCO style or from their "DRIVE THROUGH DIET" menu.
I also buy bread with about 5 grams of fiber per serving and it is lower in calories as well. I make pasta with "Smart Sense" brand high fiber pasta from WalMart. It looks and taste like regular pasta and not like a cardboard high fiber pasta. I have cooked it for friends, family and coworkers who all raved about how good it was. I didn't tell them that the spaghetti I made was low fat, high fiber and healthy or they may have changed their minds... LOL.
Anything below about 1200 calories a day will slow your metabolism and you will end up fatter than before. It took years to put the fat on so you can't expect to take it all of in a month or two. It will take lifestyle changes or you will just regain everything and more very quickly.