How do you tell a boy that you like him?

It's this boy in my class, I like him as a boyfriend, but he probably sees me as just a friend. I want to tell him that I like him, but he's always around his friends. He also likes one of my friends, Princess. I want to tell him early because if they start dating it's going to feel weird that I like him and he's saying my friend. I was thinking about telling him the last day of school or in summer. I have his kik ,but he barely even answer me on that. When should I tell him? How should I tell him that I like him?