My advice to you is try to gear up as much as possible with crafted items and ah boe stuff. My first heroic was gundrak. I still think its pretty easy because most of the bosses are tank and spank. For the elemental guy just spread your guys out so the only puddle they are standing in is their own. Your priest should be able to aoe heal through the damage. Make sure to taunt the elemental because he will go after your guys. The last boss hits pretty hard. They removed the little corner stone that kept all your guys together. What I do now is put two on once cide of the room with back against wall and two on the other. I tank the boss in the middle so when they get thrown around everyone is still in range. When I run gundrak I start on the east side entrance and do the troll and little merlock guy first. Then I exit and go to snake boss at west entrance. This keeps you from clearing that line of trolls. It makes the run faster cause all you have to clear is some snakes.

Once you start doing UK it gets easier. Be sure to not cast by moving to stop any casting during the roar. And decurse when he puts it on your guys. Aoe heal after the roar and just dps. Run through the guy on the slams so you take no damage. You will be wiping a ton once your start heroics. Just keep at it. Once you start getting gear upgrades it becomes much easier. My healer started with 1200 healing now he has about 1945. My mages had 1045 spell now they have over 1500. Just keep at it.