I’m pretty quiet too, so I feel ya. The easiest way for me to be “friendly” is to listen to the conversations that people around me are having and to jump in when I can, whether that’s to agree with someone, to play devil’s advocate, to tell a relevant story, to answer a question, or whatever. Of course, that’s how “normal” people have conversations, but for us introverts, sometimes we need to be explicitly instructed on how to do stuff like this!
I don’t think there’s anything wrong with holding out for friends you really, truly like. The point of having friends is that you’re supposed to share a mutual liking for one another. But it depends on your priorities. If you’d rather just have any friends than have friends who are totally compatible with you, that’s fine too – but of course, the goal is always to eventually find people who really “get” you. (I find it easier to make friends in a new social situation if I’m already buddies with someone there, even if I don’t even like that person very much, because it allows me to feel more natural and open when socializing with others.)
If you’re still in high school, keep in mind that things change a lot when you get to post-secondary institutions. They’re filled with people who share your interests so you’re more likely to find like-minded folks.
It’s not a bad thing to be Facebookless. Some people, myself included, find it easier to forge friendships with social networking tools, but they’re certainly not required.