Passives = people who buy-in short of maximum, players who limp rather than raise the blind when first in, callers, min-raisers especially post -flop.
Aggressives = play many tables and buy-in for max, will be 3 betting and raising a lot.
Raise and value bet the passives but don't bluff them, the moment they show aggression, fold all but the near nuts.
There are good and bad aggressors.Bad aggressors play bad lines which don't make sense.Watch for what they showdown to get an idea how they think. Usually you can bet for fairly thin value against them and make thin calls.
Good aggressors: they bluff in spots where they should show up with big hands and value bet in spots where it looks like they are bluffing