I prefer having at least 3 very low cards with 2 of them being at least A/2 or A/3, if the Ace is suited with 1 of your cards it brings in the chance to Flush.. That way if you pair one of your low cards you still have a chance to win low. Also it give you a chance to straight.
Be careful if the board pairs, very good chance someone at least has a set or even a full house. Good luck,,, PLO8 is a very difficult game to learn. These are just a few of tips I play by. I assume you know you have to use 2 cards from your hole cards in both the Hi and Lo hands.
JUST KILLIN TIME,,,WAITING FOR TIME TO KILL ME...
Because this game is hi-lo the most powerful card in the deck is the ace. That's why a lot of folks discussing the best hands in Omaha 8 always include one or two aces. The problem is there are over 270,000 possible hands in Omaha 8 so waiting for aces is not the best strategy.
First, there are only 5 cards "over 8", the 9 to the K. That leaves 7 cards 8 and under. I left out the 2-way Ace because it makes both ends of the game. You can guess that with these numbers that there will be more boards with at least 3 low cards than 3 high cards. So your first strategy is look for hands with at least 2 low cards. When your hand has 3 high cards you have no chance for a low and are severely handicapping yourself.
There are many other things to consider and discussing them would make this post way too long. Briefly, with a 4 card hand (or 5 in my favourite, Courcheval) you prefer to see two cards of the same suit with hopefully an Ace or K included. I say that because there will also be other hands at the table with suited cards and you want to start off with a chance to make the best flush in at least one suit. While full houses are always a danger which you try to avoid by being very careful when the board has paired, remember that the other players will value a low hand highly particularly if their hand has at least 3 low cards. That makes a flush powerful when facing hands that don't have pairs.
Finally you'll learn that because the game is slanted towards low hands that there will be a lot of pots with two or more hands tied for low. What you want is one of those hands that also has a good high hand component. It's always fun to win 3/4 of the pot when you win the high and half the low.