Valuing yourself is partially a matter of personality development, and partially a matter of choice. In order to value yourself, you need to feel you are worth valuing. In fact, you areworth valuing, but it often helps to prove it to yourself by attaining some objective, learning some skill, or earning some distinction. And in order to value yourself, you have to say "Oh yes, I am valuable."
Value yourself: It's a belief that you are good enough to have an opinion, have a voice, and have a say, and that your contribution does matter. It's the belief that you are capable, that you can learn to do new things and to be creative. It is your ability to be independent, and to not rely on a particular person or institution for personal well-being, and its your ability to decide for yourself and living your life the way you want it to be.
All of these things are yours by right. But they will never be given to you. You have to take them, by actually believing in yourself (no matter what others says) and by actually being autonomous.
Your school doesn't have a lesson on this. So you have to take charge of your own sense of self-worth. Do it every day. Tell yourself that you are smart, you are cool, you are strong, you are good, you are capable. Then, practice these attributes. Be smart by (say) solving a crossword puzzle. Be cool by making your own fashion statement. Be strong by doing something you said to yourself you were going to do. Be good by doing a good deed. Be capable by doing something difficult without any help. And every time you do it, remind yourself that you have, in fact, done it.
The point is how we think about ourselves is as much a matter of learning as anything else. If somebody tells you that you are worthless over and over, and if you do nothing to counteract that, then you will come to believe you are worthless, because that's how your neural connections will form. But if you repeat, and believe, and behave in such a way as to say to yourself over and over, I am valuable, then that's what you will come to believe.
Value yourself and others too will value you !
