Start with attitude. An attitude that is miserable will not succeed. But one that has confidence will. Make up your mind to do it, once and for all. Then, I started with exercise. I find it easier to diet if I am busting my butt. Hey, I don't want all of my hard work to be wasted by a meal at McDonald's. Stay on here, check out some recipes, check out sparkpeople, too for good ideas and calorie and exercise logs. Keep track of EVERYTHING! Yes, it's a major pain, but it's what will really help you see how you lose weight.
Good luck, keep me posted.