I let myself get a little bit angry, think f*** you, you don't know me. Headphones in means people don't bother you, and if the music has a beat and gets you going that works even better! Ask questions, all the time. If anyone asks how I am, I say, yeah I'm good thanks, you? Hows your dad, is he still in France? Get the conversation onto them. It's okay to drift off and not listen, as long as they never know!
Remember what people tell you, you look like the nicest person on the planet without a care in the world. When I'm on a course, stuck with strangers in an intense learning situation with no escape, I get a kick out of seeing how little I can talk about myself. Introduce yourself with a smile, then ask a question, then another, and another, until the other person is onto a topic they know really well and love to talk about. At the end of the last course I did, one girl said I was the most interesting person she had ever met. She knew my first name, and where I go to university. I knew her childhood pets names, her boyfriend's annoying habits, all the stupid irrelevant stuff people want to share but never do.
Smile. Talk with a smile to everyone, joke about workloads, stupid things you've done. If you are always telling stories about how you did this, tripped over that, said this really embarrassing thing, people don't realise you aren't saying the important stuff you save for your friends.