moving back towards advise for starting conversations, if your lucky your school/uni will have a lounge/common room to hang out in, just turn up sit near people your familiar with, just going to the same classes is enough, and listen to the conversation until you have something to say. Then join in.
That should work unless your actively shunned, being able to tell what's a private conversation and what isn't is recommended too
Another trick I've learnt is that people like taking about themselves, dad recommended asking "what was the most interesting thing in your life" as an opener. I never actually tried that one though but people generally are happy to answer. Its a bit hit or miss weather you start a conversation or small talk with this one though.