* They make an effort to be around you. They might always want to sit next to you in class or find ways to talk to you outside of school.
* They are kind and respectful. They might open doors for you, let you go first in line, or just treat you in a generally nice way.
* They are jealous when you talk to other guys. They might get upset or even angry if they see you talking to another guy.
* They do nice things for you. They might bring you a snack or drink, or help you out with a project.