Remember that you only play to scoop the pot, so after the flop, if your high hand is not a certain winner and will probably have to split with the low, or if you are playing for low and don't have a decent shot at the high hand, usually check/fold and get out early.
Slow play most Omaha hands. It is very difficult to run players off in this game and early raises are risky unless you know you can't lose.
Usually avoid playing middle suited connectors. Hands like 8h 9h that are often very playable in Holdem and Omaha high, are bad news in high-low split. To make the high end of a straight, you have to catch the cards that will also qualify low hands. To play these you also need a suited ace or an A2.
Don't overbet A2, A3 and 2 3 nut lows. These are often shared with another player and you can end up getting 'quartered'. In other words, if there are 2 playing the same nut low and one going high, you are in a situation where every bet you make contributes 1/3 to the pot that will only pay you 1/4 back. You do better if you can check around. Fast play in this situation only makes you money if there are 3 or more other players with either high or losing low hands.
Watch out for uniform flops, like 8 7 6, they can easily turn into straights that can overtake your high pair trips, or other good hand.
Beware of Suited Flops that can make a completed flush. In this case, you should usually hold the nut in that suit, or have trips or two pair that can fill up.
Check the raisers chips. Players that are close to all-in often rush the betting just to get all their chips in a sink-or-swim last hand.
Study your opponents, especially when you are not playing hands and can pay careful attention. Do they find more hands to play than they fold? Do they bluff? Can they be bluffed? Do they have any 'tells' (give away mannerisms) that disclose information about their hands etc.
Get caught bluffing once in a while. It is a way to vary your play and not be too predictable. You win pots that you don't deserve when your bluff works. You lose a few chips when it doesn't work but it will get you calls from weaker hands down the line when you are really strong and need the action.
Pay very close attention to your cards. Omaha Hi Lo hands can get confusing and it is sometimes easy to think you have a nut hand winner when you don't, or have the best possible hand and not realize it. Be careful to avoid these costly mistakes.