I almost never raise pre in O8. O8 is a drawing game and as far as I'm concerned, my hand has no real value until I see a flop.I look for A2xx, preferably if the x's are also wheel cards, and/or one card is suited to the Ace. You want 3 or 4 separate low cards to reduce the risk of counterfeiting, but you can play 2 for cheap. Seriously, if I'm seeing a flop, more than half the time it's with A2. And yes, I'm folding a LOT, but that's a lot of spew I'm not donating to the rest of the table.A3xx is playable at LP or at passive tables. AAxx is very overrated in LO8 unless you have wheel cards to go with it, because it rarely hits a flop hard and usually gets outdrawn for hi. Half the time I see a preflop raise whether live or online, the player has AAxx, and they don't take anything down half the time.If several players have called, I'll play a high only hand like KQJT in LP or from the blinds, even for a raise. I can dump it if the flop comes 2 or 3 low. I think of hi only hands like you think of Ace-rag suited in HE, but make sure no card in a hi only hand is lower than a 9.Same with 23xx: I play it for cheap in LP and dump it if an Ace doesn't flop.I only complete the SB with the sort of hands I mentioned above. Seriously, even if I have great odds, I'll still dump it. Half a bet here, half a bet there, and suddenly you've got a leak.Of the 5278 possible O8 hands, there are only 9 or 10 profitable hands that don't contain an Ace. Basically, if I don't have an Ace, I muck it unless it's an aforementioned hi-only hand or a good 23xx and I can see a cheap flop. Even when I do have an Ace, I won't play any hand worse than A4xx, which itself needs a ton of help to spike the nut low. I muck A5xx, A6xx, etc.If I'm not sure whether to play a hand, a good basic rule of thumb I follow is to look at my hand and find the worst possible Hold'Em hand out of your 4 cards. If I wouldn't play that in Hold'Em, I muck.Bill Boston wrote a great book (helpfully entitled Omaha Hi-Low) that focuses extensively on hand selection and profitability for each hand. The book also has a complete chart of the EV for literally every Omaha hand possible. I'd give that a look if you're still unsure about hand selection but want to expand your selection. Or, better yet, you can learn Hutchinson's Point Count System
, which is fairly reliable in determining when to profitably play an O8 hand because it doesn't overrate pocket pairs like most point counts do. You can learn it back to front, follow it religiously, and over time you'll get enough of a feel for what hands are playable that you won't need it after a while. I used it some and it proved helpful for minimizing my spew while putting me in profitable situations more often.