[chaos]

A general rule is the more cards you get to see in a hand, the stronger the winning hands will be and the tighter you should play.

So you should be playing fewer hands preflop in Omaha/8 than in Hold'em.

In loose games with a lot of people seeing the river you would want the nut low or a very strong high. If the flop has two of a suit and the nut high on the end is a flush in that suit, you want the nut flush. If the flush only had one card on the flop and both the turn and the river brought cards to make a flush (often called runner runner), than less than the nut flush may be good. If the board is paired you want either quads or the highest possible full house. If a straight is the best possible hand you want to have the highest straight possible.