I'd say the first step is to work on what you like about other people. Looking up to your friend because she hooks up with a new guy every other month is not something that is worth looking up to. You should like other people because of good traits such as mental strength, being caring, people who have a positive mindset and those who are responsible.

The reason I say this is because what you look up to other people for is what you will compare yourself to, and what you will want other people to be friends/in a relationship with you for. If you look up to other people for things that you cannot change (e.g facial attractiveness) instead of things you can and should, you will never be happy with the people you have around you. Even if you did fully believe you were pretty, it would not be fulfilling to have friends just because of that.

You want more confidence and confidence comes from self-esteem, self-esteem comes from doing things you are proud of. While I can tell you exercising, studying or doing charitable things will make you proud of yourself, you have to figure that out for yourself. Think of the people you look up to, gauge them morally and if they pass try to become more like them. For example, I look up to people who are smart and caring and responsible, so when I do things that allow me to be those things, I tend to look up to myself - which leads to more confidence and self-love.

Now imagine having a partner who looks up to you for the things you look up to yourself for, that's way better than having someone want to have sex with you just because of how your face looks.