Variance
(Or, "I'll have the rent for you next week. Really.")
The thing is this. If you can't spot the variance in your first half hour at the table, then you ARE the variance! Uhm, no wait, that's another saying. Variance is basically the monetary swing in a game--that is, how much you can expect to win or lose each session. The higher the variance the higher the swing.
The biggest factor that affects variance is the aggressiveness of the table. If the table is very aggressive (especially if there are one or more people on tilt and you find pots getting capped preflop and beyond consistently) then count on high variance. If you do not tighten up several notches above the level of the table then you are going to go for a very very wild ride.
The best sorts of hands to play during this sort of table (assuming you don't just leave which is another viable option) are JJ, QQ, KK, AK, and AXs (throw it away if you don't flop a flush, flush draw or two pair) and unless you flop something huge be prepared to check and call to the river. You can also play any other pair through the flop but dump it on the flop if you don't flop trips. If you DO flop trips raise whenever you can, do NOT try to slow play.