When there's a big enough pause in the conversation(one topic is dying down and another is beginning), start your own topic.
Example:
person1: so yeah, that [whatever] was pretty funny back there...
everyone else: Haha yeah...
[PAUSE]
You: so did any of you guys see that new movie that's come out?
this should start the convo in a new direction under your control. hint: try to make it a topic that you are genuinely interested in, this will ensure that you remain 'in' the convo and don't get butted out by people that are just talking loud and making noise.
Also, watch the news and keep track of sports scores, etc...this'll give some nice convo's with you again as the 'lead man'.
Talking loudly works too.
If it's a social setting, don't be afraid to shut someone down if they say something stupid(in a joking way of course). This generally gets a laugh out of the rest of your buddies and sends out the 'dominance' vibe.
If you're all just milling around hanging out somewhere, take physical control of the group by suggesting going somewhere/doing something more fun, etc. Think of something decent while you aren't talking, and suggest it in a commanding tone in one of those pauses i talked about above.
Try to refrain from too many questions or you'll get bumped down the social ladder and it gives people a chance to act condescending towards you.
Be the man with the plan! act like a leader, not a follower(do what YOU want to do, not what THEY want to)...and people will follow if they think your idea would be more fun.
FYI this all comes from experience, there's no philosophical bull**** in there.
and one more thing that I thought of, because you're gunna be pretty new to these people you're meeting: because you're the new guy, they're gonna be testing you...giving you verbal punches, etc..generally not respecting you fully yet. For a situation like this, draw a line for yourself somewhere between Not taking **** from ANYBODY, to not being an uptight bastard who can't take a joke.
Play it cool.
