Brandi:
Tell yourself 20 times each morning and 20 times each night that "nobody's perfect." Say it over and over and over. Then say, "I'm beautiful" 20 times every morning and every night. After a while, your brain starts believing what it's hearing and your whole attitude will change. Trust me, this works -- for just about anything! The trick is to always use the present tense in your statements (for example, I AM beautiful, not I WILL BE beautiful).
I used to be my own worst critic and didn't think I stacked up to anyone. I started telling myself over and over, "no one's perfect" and "everyone has problems" and "I'm just as good as everyone else" and "everyone has to get up and give a speech, too, so they're just as nervous as I am, so I might as well do my best" and stuff like that. This kind of self-talk has worked wonders to improve my overall image and how I do things.
I'm to a point where when I go out, I don't care how people see me. I know that I'm not Miss Socialite, so I don't try to be, and that's okay. I wear what makes me comfortable, regardless of whether some think it's too casual or not sexy enough, etc. In other words, I'm true to myself and don't do what others expect of me, I do what I feel comfortable doing because to do anything else is false...so if people don't like me for me, then to heck with them. Granted, you have to have developed a certain amount of confidence to get to that point where you can say "I don't care what you want; this is me", but it's a great feeling when you get there!