Omnotron's a cluster of ducks -- and trying to explain it all to someone who's new to the fight makes the thing sound like a hot mess of chaos and impossibility. It can be difficult to keep all the elements straight in your head, especially if you're simply going by lists of abilities.
Once you've seen the fight a few times, though, it gets a lot easier. All of the boss's abilities are clean and obvious; you can't miss them. There are literally neon lights flashing above your head that will make sure you know things are about to happen.
The challenge for a raid leader is how to introduce all these elements to a raid group and organize the dynamics mentally for both himself and his raid members. Simply reading a list of abilities won't get the job done. In a sense, the raid leader's job is to interpret information from strategies and videos into actionable, messageable information for the raid.
A few things at a time
Try and break down the fight for your raid into a few elements at a time. There's been study after study saying that the human brain can only remember a few "things" at a time until those "things" become ingrained reflex.
Using Omnotron as an example, I'd start with these three essential things:
Kill the latest robot to become active.
Do not hit robots with shields up.
If you get Lightning Conductor or the Read Beam of Death, get clear of the raid.
I admittedly don't tend to warn the raid "don't stand in stuff." As a general rule, I expect anyone who's been through normal instances, heroic instances, and any raid before from ... like, ever ... to avoid standing in things.
It might surprise you how often focusing on a few things at a time can lead you to success, even though you might not be highlighting every raid dynamic. That being said, a complicated fight like Omnotron usually needs a little more explanation than just "kill that, avoid shields, get away."
Since you have those previous three dynamics down pat, your team can now focus on the newest abilities.
Discuss what went wrong
We learn by doing, moreso than from reading or watching. An eidetic memory doesn't necessarily comprehend and interpret the information from rote. The best way to learn is to tackle a concept, discuss it, analyze it; this technique promotes understanding instead of simple repetition. You'll get more mileage from understanding than from simple reflex.
After each wipe, take a few minutes and discuss what happened. Does anyone have any particular feelings about what went down? Healers especially may have important input for your team.
Taking the time for a quick team discussion will make sure you get to improve your strategy. More importantly, it'll help promote understanding of the fight among your team. That understanding will go further to advancing your progression than simply reacting to a shopping list of boss abilities.
It takes some time
The downside of these tips is that they take time. If you're only talking about three raid abilities at a time, you're probably going to wipe while you learn all the boss attacks. If you're taking the time to discuss what went wrong, that's more time you're spending.
In my opinion, the time is worth it. Raiding should be fun and not simply full of frustration. If your raid members can't even make sense of your explanations, the raid will become annoying very quickly.
Ready Check shares all the strategies and inside information you need to take your raiding to the next level. Be sure to look up our strategy guides to Cataclysm's 5-man instances, and for more healer-centric advice, visit Raid Rx.