Be approachable and outgoing!
Have a sense of humor
Find something you have in common with someone
Be nice and talk to different people at school
Approach people in the social event, sports team, or club
Invite someone to hang out
Invite the friend to hang out with you and a group of friends
Once you are close enough and have hung out with the friend buy each other a friendship bracelet. (This is optional, not really tho)
YOU NOW HAVE A FRIEND!