Hello, congratulations on reaching the end bosses. Cho'gall has an enourmous amount of abilities and skills to watch out for but in my opinion is relatively simple. A few tips and tricks we use:
Have the prot pala tank the boss, so he can clear worships with avengers shield.
Make sure you are using DBM, and have the announce shadowcrash near you option ticked.
With the amount of ranged aoe you have the festering blood should be a breeze, make sure the hunter is getting a slowing trap down, when they are out of that get the destruction lock to shadowfury them, frost/fire mage nova them. A tip for the warlock, use summon infernal on the last wave of adds (usually 4 waves in our case) really cleans them up fast. Ring of frost u also good for emergencys.
When you get to the last phase, spread out a bit for all the people throwing up
and make sure you nuke the tentacles fast interuppting their cast. They are stunnable so things like shadowfury, HoJ work wonders.
Best of Luck.
Destron - Twilight EU