Chances are likely that you wish to change something about your lilfe that has to do with your health or physical appearance. It is also equally likely that this won't be the first time you are making this pledge to yourself. Instead of giving you suggestions on what to change, I'm going to describe to you how to structure your desires so that you have best chance to acheive them all.
When I teach my clients about weight loss, I always ask them to list on paper three goals. One is at 30 days, one at 60 days and one at 6 months. These goals need to be achievable (losing 10 pounds in a month is not a realistic goal if you plan to keep the weight off) and they must be quantitative (able to be measured). Usually it is a weight loss number, amount of servings of the "right" foods (read as veggies, water intake and lean protein), or inches on body parts. Stay away from goals such as "toning up", because if you are tough critic, you will never be satisfied and you will never have an end date. The first goal gives you short term gratification, the second keeps your momentum going through the second month, and the six month goal is your long term stretch. By the second month, if you have stayed on course, your lifestyle is changing permanently and you have a very high chance of going all the way. It's the first 30 days that are the toughest, so buckle down, think about what you'd like to do, and like Mom said, take manageable bites!!!