Just like my advice for playing no-limit holdem, your goal should be taking your opponents entire stack when playing PL Omaha/8. This is done by only playing hands with potential to scoop the pot. Remember that often there is no low possible so high only hands can be valuable. Many new players make the mistake of overvaluing big pairs in starting hands. Big pairs must improve in order to win. Also after the flop, made hands with redraws to better hands are the ones that make the most money. In addition, drawing to just a low hand is a quick way to going broke. Especially if the pot is heads up or three handed, even if you hit your low hand you may have to split and if you don't have a chance at high you will lose money.
Texas Hold'em Rules & How To Play