I think attacking one problem at a time is the best way to go about (at least for me). I noticed that many people try to make drastic changes all at once and then fail at all of them. I'd recommend trying one thing and just doing that one thing above all else. IE, don't try to exercise and diet at the same time. Pick one and when you've firmly established the habit, start the next change.
What usually happens is that people are not aware of how many calories they eat, so when they start dieting they change the high fat calories food for low calorie ones (fruit, vegetables, low fat protein) plus the exercise they enter in a severe caloric deficit that is not sustainable.