You will typically see a lot more limping pre in Omaha because so much can change on the flop and each street regarding hand strength but its something you should also try not to get cought up in.
You have 4 cards as opposed to two and many might view it as having 2 sets of 2 cards so might think a good hand is 56TJ for example because of the two straight possibilities but you need to look at all combinations and there are 4 of your possible 8 two card hands that just suck 5t, 6t, 5j, 6j and even if these are double suited its not that great because when looking at a flush in omaha you want to be on the nut side of it.
So looking to have 4 cards that work together AKQJ, especially double suited is a great starting hand or 9TQJ could be deemed even better because it has a lot of straight possibilities....for example you get see a flop of 78x well now you have 4 card that can give you the nut straight 6, 9, T, J......such hands are also called wraps because of the straight potentials.
Many times if the nuts isn't in your hand its very possible in someone elses, unless you have blockers which brings in the bluffing
aspect of omaha, but if the board pairs very good chance there will be a boat out there.
Many people will only 3-bet big pairs and the best hands pre for calling them are wraps and then eval your potential when the flop comes.
Just some quick pointers, its a great game I love it but also has some high variance because people often have more ways to suck out on you so can find it even harder to lay down to raises.