See also
11. Good table position is extremely valuable. Out of the fear of giving free cards, the opposition is more likely to bet their good hands. Thus, the check-raise is used much less frequently in Omaha than in hold'em, and a check is more likely to indicate weakness. Moreover, it takes a much bigger hand to bet into a field than it does to bet when everybody has checked to you. This makes acting last - and being in late position in general - a major advantage, as the pot is often ripe for the taking with one pot-sized bet regardless of your own holding.
The player who acts last can play more comfortably in situations with holdings that would otherwise be difficult to play from up front (including Aces, trips, two pair, the underfull, or a set on a draw-heavy board), has better implied odds when he flops trips, has some flexibility when flopping the nuts, and has interesting bluffing opportunities not available to the players who have to act first. The positional advantage is also of great importance in heads-up confrontations.
12. Build the pot early with your big hands and big draws. Not only is checking the flop with the nuts a good way to lose a big pot should a free card beat you. It is also a good way to win a small one. If you bet the full size of the pot on the flop and get one caller, you can bet three times as much on the turn; if you then bet the pot on the turn and get called again, you can bet nine times the original pot size on the river. By checking the flop, you are ensuring that the end pot will be small; by betting, you are giving yourself a chance to win a big pot should anybody have anything to call you with.
The same is true of your big drawing hands, the smallest of which (the 13-card nut straight draw) will hit by the river roughly half the time. You want to build the pot early so that when you hit and the opposition makes a second-best hand, they can pay you off with a big bet rather than a little one. You don't really mind if they fold, either.
13. The wore players in the pot, the less poker you play. This is true in hold'em as well, but is especially true in Omaha. The more players in the hand, the more you should focus simply on playing your own hand rather than trying to see "through" an opponent's bet.
For example, let's say the flop comes T-8-7. The first player bets the pot: if you were heads up before the flop, you might call him with two pair or the sucker straight and see what he does on the turn. But if there are six players in the hand and one of the blinds leads out into the field with a pot-sized bet, forget it: About 99 percent of the time he is going to show you the nut straight.
14. "Give the opponent credit for having what he represents". That gem comes from Bob Ciaffone's must-read classic Omaha Poker, and is related to the previous point. The gist of it is that you have to be willing to be bluffed at times if you want to be a winner at this game. The example that Ciaffone uses is where the flop conies J-J-3 rainbow and an opponent bets, representing at least trip Jacks.
When you hold a straight or two pair and there is a flush on the board, you are done with the hand if some-body bets. Consistently calling down through the river with non-nut flushes and second-nut straights is a good way to go broke. And when you bet out with middle set or bottom set or two pair and get raised, you are probably not in good shape. With a set, you are usually either a huge dog to top set or a small favorite to a big drawing hand, which is not an attractive proposition. Two pair is toast against either hand.
In contrast to hold'em, there is not a lot of naked, unadulterated bluffing in Omaha. More pots are contested multi-way in Omaha, and the action in Omaha is driven more by hand values than pure aggression. More often than not, the bettor will have what she says she has. If she has just the dry ace and not the actual nut flush, then good bet: you don't want to spend a lot of time (or money) playing bluff catcher in PLO, especially when you are first starting out and are just getting a feel for the game.
