After everything you've previously learned about poker, Omaha Hi Lo takes you to another level and a new way of thinking. If you want to be successful your approach can no longer simply be to win with the best hand; you now have to think of ways of winning with high hands, low hands and, if you really want to do well, both at the same time!
The holy grail of all Omaha Hi Lo hands is to win both pots ("scoop the pot" as it is known) in one go, which is possible to do with the four cards you are dealt in your starting hand. Although you MUST always use two cards from your four hole cards, along with three from the community cards, to complete your five-card hand, you can use the same hole cards to help make both a high and a low hand.
For example, if your hole cards were A-K-J-2 and the board was showing A-A-8-5-3 then you could use the Ace and King to make a high hand of A-A-A-K-8 and the same Ace, along with the 2, to make a low hand of 8-5-3-2-A.
When you're making a low hand in Omaha Hi Lo you do not have to worry about straights or flushes. You are simply looking to make the lowest five cards possible. The lowest possible hand therefore is 5-4-3-2-A (known as "The Wheel"), the next lowest possible is 6-4-3-2-A and the next lowest after that is 6-5-3-2-A. In all it is possible to make 56 different qualifying low hands in Omaha Hi Lo and you can find them in order of rank here.
Whenever possible in Omaha Hi Lo you should be looking to start with hands that give you the chance to win both halves of the pot and when that isn't possible you have to try and determine which part of the pot your opponents are looking to win. If they start betting out vigorously when a low card appears on the turn then it's probable that they're after the low pot. If you're concerned primarily with the high hand then you might be looking at a split pot.
In those circumstances though always try to ensure that your high hand is not too weak, as the player looking to win the low hand could still surprise you and pick up both halves of the pot, even with a high pair or two pair.
A general rule of thumb in high-low split games is to look for starting hands that contain good low cards, especially those with a suited Ace. Whereas a low hand can go on to win the high half of the pot as well, a high hand can NEVER win the low pot!
It is important to play tight because so many players, attracted by the possibility of winning two pots, tend to get drawn into the action and it can be very difficult to win hands when you yourself are playing marginal cards. When you go into the action with the very best cards you give yourself a significant edge over those players whose choice of starting hands has been less selective.
Once you've played Omaha Hi Lo for a few games you'll come to understand the varying skills and tactics required, and also the different starting hands that will bring you the best chance of success. Always try to play hands that will either win you both halves of a pot, or the whole pot if there are no qualifying low hands. This is the key to becoming a good Omaha Hi Lo player.