What are the stakes and the dynamics of the table? Is everyone limping? How often are there PF raises...and at what multiple of the BB do raises take?

If everyone is limping, the SB and BB could be on any two cards.

What happens post flop? Passive checking? Or a lot of action?

Without knowing more, I am guessing this table is playing loose and passive. The collective hand ranges could then constitute neary every possibility...especially all suited hands, all Ace-anything, middle to high o.s. connectors.

If your preflop raises with premium hands do not reduce the field, try raising more. I'd avoid getting fancy by slowplaying or check raising. Play premium hands for full value. Maybe play Ax suited more often...as well as other hands that fair well in multi-way pots.