I think holidays are the best time to start this! Here's what I've been doing:
Portion control. I eat the types of food I want (although I really do try to stay healthy, with fiber, veggies, fruits, lean protein, almonds...etc) but I just cut the portions in thirds. This way I don't have to count calories. So whatever portion you were about to put on your plate, reassess and put 1/3 of that. Another helpful tip is to use your bread plates instead of your meal plates. Do this with EVERYTHING. If you were about it eat a candy bar, eat 1/3 of it instead and put the rest back in your pantry or your book bag or whatever.
(My exercise routine is more to facilitate the healing of my back issues so I'm not going to really include it here as a way to lose weight but, it probably helps as well.)
Anyways, I've found the portion thing always works the best for me because I never feel like I'm cheating myself or dieting. I've kinda made it into a game...how little can I put on my plate and be satisfied? You'd be surprised.