It's been said that to win at Omaha you needn't be a great player just competent. Also you need the ability to discern who the fish are-players who constantly make mistakes. My question is to develop these skills? What resources are available to put one on the fast track in this area?

Becoming competent would be referring to developing a very solid strategy based on fundamentals that while not being the most optimal is going to lead you into more profitable situations and easier decision which of course you can slowly build on and work towards a ln optimal and winning strategy over time.

In order to identify the "fish" in a game, you yourself must be competent in the game as you need to be able to quickly spot fundamental mistakes. The biggest "fish" in a game aren't those that are making mistakes in spots with close decisions, theyre generally those making huge fundamental mistakes in spots that aren't even close in the eyes of someone experienced. Quick example is a player playing a very wide range of hands, aka garbage hands OOP often.

To develop skills that will point you in the right direction I can suggest starting with some videos, maybe a book if you're very very new to the game and then using this to start using the right thought processes in hands which you can then apply yourself and then start posting hand histories to get a second opinion on spots.

Finally - practice practice practice practice. Maybe analyse your own hands, see where you could have taken a different line, challenge your own plays that you think are okay and see if there's room for improvement.

Learning poker is a grind and takes a lot of time and dedication.

its more difficult to be a competent omaha player than hold'em because the mechanics are more involved, the strategy changes more from full-ring to shorthanded and because the 'pot-limit' constraints are tremendously important relative to stack size

There are some ok books on the subject that should prepare you for live cash games and teach you enough to beat weak lineups. The gap between a competent and a good player is quite large with <6 players.

Identifying fish is pretty easy, and its always relative. I'll post some more on it later.

To be fair, I don't play much holdem but honestly the game can get super deep and complex in some games and it honestly perplexes me. That could be a function of my lack of practice and knowledge but I believe at the highest levels they are equally complex just in a different way.

my comment was more about reaching the 'competent' skill level, which I define as good enough to beat weak lineups consistently and not much else

Pro/expert level showcases different skills and knowledge, reaching that level in no limit is extremely difficult