The first situation is when you have AA and you are the first or second to act.  In order to have a shot at winning the hand, you are going to need to eliminate some players and the only way to do that is to get some money in the pot.  When you are first or second to act, it is early enough to dissuade callers from getting into the pot with a marginal hand.

You are also going to have a better idea of where your stand against your opponents if they are getting into the pot. As it is unlikely for someone to call you with a marginal hand, you can count on the fact that you are sitting across from a hand that has a high pair in it.  If the board flops babies, you can continue to be aggressive with a little more confidence that you are still sitting on the best hand.  If a K or Q hits the board and you fire with them coming right back over the top, you are probably better off letting the hand go as they will more than likely be sitting on a set and you are reduced to 2 outs.

The second situation where you can throw out a raise is when you have a lot of limpers already in and you are in late position with a drawing hand.  The reason for this is to build up the pot on the hopes that you hit the flop in a big way.  The beauty of this move is that most inexperienced players will check it around to you regardless if they hit or not.  They will hope to hit you with a check raise and if you don’t hit, you have the ability to get a free card on the turn.

Raising here is very effective over the long run as the odds that you are generating off of the initial raise are rather large when compared to the overall investment that you are seeing back on your hand.  If you manage to hit one out of about 8 hands, you will be at the very worst even.  If you can hit two of these hands, you are going to have a very profitable session.

Raising in Omaha is a true weapon and you have to use it wisely.  Don’t abuse it and after you hit a few hands you will be able to pull off a bluff every now and again.  You of course need to mix up your game a bit so you don’t become predictable, but stick to these guidelines for the majority of your play and you can turn profitable sessions when you are raising before the flop.