Yet another link to an article that basically serves to remind me that I must get moving! All kidding aside, the point of the article is basically sound - take in fewer calories, burn a few more, and you will gradually get in shape. A couple of other simple techniques to improve the quality of a resolution (whether fitness or otherwise) include:
1) Set goals that are within your control, rather than out of your control. For example, if we were discussing golf, one could set a goal of shooting a round of 75, as opposed to "winning a tournament." The first goal is within your control, the second one, however, depends a lot on what other golfers shoot.
2) Numbers, number, numbers! Goals are much more attainable if one attaches specific amounts to them. It is more effective to state, "I want to lose 10 lbs.," as opposed to saying, "I want to look good," or "Look like so-and-so." Be as specific as possible.
3) Time frame - along with #2, set discrete time periods, so that you can measure your progress in increments, and make adjustments if necessary. Simply saying, "i want to lose 10 pounds" provides no motivating power, and allows for all sorts of mental gymnastics to delay and procrastinate. Setting a reasonable time frame not only motivates you, it also allows for an accurate, ongoing assessment of how well you are achieving your goal. For example, many people hit the gym hard in January. They are legitimately working hard, but at the end of two weeks, they've only lost two pounds. If a person doesn't have the mind set of losing one pound per week for 10 weeks (which is reasonable), they may become discouraged, and quit.
4) Energize and educate yourself - I always recommend that individuals provide themselves with consistent information on a topic. We tend to perform better in areas that we have confidence, so regular reading about a topic, writing about it, etc., can help motivate us long-term. New ideas can also provide motivation. One of the reasons I continue to subscribe to Men's Fitness, even though most of the articles have started to look the same, is that reading about fitness continues to motivate me towards fitness. And, the occasional suggestion that is new provides me with the impetus to try it out myself.
5) Frame goals in the positive - this would seem to be a no-brainer, but surprisingly, we still often think in terms of the negative. A simple example would be to say to a teammate, "Get a hit," as opposed to, "Just don't strike out." The problem with the second statement is that, despite the "don't" in the sentence, the image that is created in one's mind is that of striking out, and we tend to do what we think about doing. A fitness example might be, "i will eat healthier," instead of, "I need to stop eating junk food."
6) Last one - do it with someone else. Again, a no-brainer, but many people, especially at the beginning, tend to be self-conscious, lack confidence, etc. However, working on goals with others has numerous benefits, both direct and indirect. Get a running or workout partner, diet with a friend or spouse, etc., and you'll find you stick with it longer, look forward to it more, and improve your social connectiveness.