Since you're in school, definitely start talking to your classmates! People DO meet in groups, because otherwise you're just one person. But school is a group, like others have said on this thread.
This is what I've done this semester to make acquaintances/friends:
1) Smile and make eye contact with the person sitting next to you (a girl, in your case, if you want a relationship).
2) Make small talk before class when you feel the time is right (ask about an assignment, compliment style, etc.).
3.) Ask if she'd like to come over to study for the upcoming test, or meet in a cafe, etc. That way, you are doing schoolwork while getting to know someone.
I'm not sure if that helped, but if you seclude yourself, it's obvious you will not have contact with others. You have to meet someone and get to know them before you start a relationship with them.