You are not just nervous, you have a good reason to be nervous. Some people just naturally attract friends, others have difficulty. It is okay either way.
What I do is go up to someone I think is kind, and might make a good friend, and I test them. I introduce myself, and yes, it is nerve-racking, but I do it. Then you just start up a conversation about anything. Ask them where they're from. Ask them about their hobbies, their convictions, anything. Once you get talking, it will get a lot easier.
If this doesn't work, then go out alone. Maybe you'll meet someone.