How to Be Happy With Your Body

1.  Remember and believe that you are made to be as unique as you are. There is no one else on earth who looks (or behaves) exactly like you. No one else has your same features and physical qualities. Perhaps similar; but never the same. Appreciate your specialness! You, as a loved human being, are the pinnacle of Creation. You are set apart; above the rest of Creation. Learn to enjoy your place of honor!

2.  Remember that it could always be worse. Instead of focusing on what you think is "wrong" about you & your body, realize that it could always be worse. You could be sicker, heavier, more frail, older..... The list goes on & on. Quit focusing on ways that you think you've "failed", and start focusing on your blessings.
3.  Remember that you have certain qualities that are complimented by other people, and that certain aspects of your body and/or personality are liked by others. Remember those times when a friend has mentioned that she likes how you do your makeup; when your girlfriend felt your biceps and was impressed; how you always get complimented on the color of your eyes; or how your lips always get compared to some movie stars' lips.
You do have attractive, likable features!
4.  Wear clothes made to fit your body type well. Wear clothes that flatter your body and/or accentuate your best parts. If you're not sure how to do this, do some research! You probably won't have to look farther than the nearest woman-specific magazine rack.
This includes, (but is not limited to): wearing blouses that draw eyes away from your chest if you're extremely well-endowed up there, wearing blue if people say that blue really brings out your eyes, and wearing skirts that are the right length for your legs & torso, to elongate you.
In other words, if you're short, wear clothes that will elongate your body, if you're heavier, wear clothes that are slimming, etc....
5.  Do your part. Eat healthy foods (like whole grains, fiber, & fish) and exercise (experts recommend 30 minutes of moderate daily exercise for optimal fitness). When you are changing your diet & lifestyle, it may take awhile for the pounds to drop off or the muscle to build. But keep going and be proud of the fact that you are doing something to better yourself.
Taking care of yourself will instantly make you look more attractive (to yourself, and to others), because you will gain confidence, knowing that you're bettering your body, heart, and life.
6.  Change your mindset. Instead of making your goal to drop 20 pounds, start thinking about getting healthier, like dropping your cholesterol by 20 points.
Research has found that a heavier person who is physically fit & active is still much healthier than a skinny person who is sedentary. So get out there, eat healthy & exercise, and be more concerned about being overall healthy than about losing weight. The weight will probably come off anyway.