Most people in high school are incredibly insecure, they usually just feint confidence. Infact, I'd say I have the same problem as you, I read that conversations are kind of like fires. If you can make it interesting, like say, "Did you hear about Facebook's stock going down the drain?" or something. Don't say, "Do you like to lick bark?" or "Craaaazy weather we're having, huh?" If you can't find anything else to say, treat it almost like an interrogation, (ask why, where, how). Most people see their lives as boring hellholes, anything could be interesting to them.
