Are you actively seeking a boyfriend or are you taking a passive approach to this? If there's a guy you really like, build up the courage to talk to him, then hang out with him to see if you're compatible, and if you like him quite a bit after that point, then ask him out. If you aren't really interacting at all with the opposite sex, that would be the real root of the problem right there! A lot of guys are quite shy about romantic matters and you may find out someone's had a crush on you the whole time and you didn't know it. Besides, hanging out with guys more will expose them to your personality, and they may very well enjoy being in your company to the point where they may ask you out, or you may enjoy their company so much that you may ask them out!
Of course, you may end up in the "friendzone", but it's better to try and be rejected than to not try at all when it comes to love, if companionship is something you feel you desire!