If you're unhappy with your life, change can seem overwhelming, but changing your life for the better can be as easy enough as using behavior modification techniques to break those bad habits that lower your self esteem and increase the positive behaviors you would like to increase.

1. The first step in any program for change is always to identify the problem. Define explicitly what behavior you would like to change, and decide what you would like the end result to be. Studies have shown that trying to cease practicing a certain behavior is not as effective a motivator as setting one's sights on the ultimate goal: for example, rather than trying to stop biting your nails, decide that you'd like to maintain a neat manicure.
2. Next, define how you will observe and measure your progress. It is important to set check-in points, such as when you wash your hands before each meal, when you will actively note whether or not you are adhering to your plan for change. In addition, there need to be observable degrees of progress (how many nails are unbitten or how long each nail is, for instance) so that the difference from one day to the next can be charted.
3. Record baseline data-how often you bite your nails and when-without changing your behavior for a week. After all, you can't see progress if you don't know of where you started! Take note of the cues that precede the behavior, such as hunger, watching television, nervousness, and so on. Sometimes bringing awareness to the circumstances that prompt you to indulge in your bad habit can help you avoid the urges by anticipating what might trigger them.
4. Now it's time to formulate a set plan to either increase or decrease the "target behavior," in specific terms. Like your start point and the progress checks, results must be quantifiable, to ensure that your goal is achievable, and that you will recognize when you've accomplished it. Commit to adding an hour of exercise time to your day, or to maintaining nails an eighth of an inch past the end of your nail bed.
5. Choose an activity you enjoy to reinforce yourself when you do make positive change. Rewards can be as simple as treating yourself to dessert if you manage to keep your nails intact, or buying a new pair of shoes after a month of 60 minutes of exercise, 5 days a week. Pretty much any thing or activity you enjoy can be used as positive reinforcement. The key is to set incremental goals within the larger objective, and reward them, as steps in the right direction. (In psychological behavior modification research, rewarding these "successive approximations" of the target behavior has proven the most effective way to reach the ultimate goal.)
6. After you've decided when and how to reward yourself, begin implementing changes in your daily life to bring you closer to your aim, and reinforce yourself according to those preset conditions. If you need accountability, find someone with whom you can check in at designated points to make sure you're not skimping on change and overloading on reward. At the same time, be sure that your smaller goals are not so hard to achieve that you become discouraged. Note and chart your progress in a notebook or on a spreadsheet. Seeing your progress on paper makes all the difference in perpetuating your motivation to continue towards your destination.

With these simple steps, you can effect the small changes, one by one, that make up the meat of the larger change you need in your personal pursuit of happiness. Little by little, you can transform your life and yourself to achieve a self-actualization specific to you, whatever that may be.