If you can gear your tank up first. Establishing aggro and holding it is the key to any heroic. Most of the best boe epics for tanks are pretty cheap now for the starter ones. Titansteel shields are 130g on my server now where they used to run in the thousands as an example. Buy your tank the best stuff you can right off the bat. As far as random heroics you will get groups but when they see your toon with 22khp they will laugh and leave. Buying yourself all the best stuff you can get right away will make it so much easier on you. My team is over 25k gearscore combined and sports all lvl 219-through lvl264 gear and if I screw up on a pull and lose aggro such as the dam 5 packs in heroic PoS on the hill to tyrannus the dam mobs can and still do wipe me sometimes. If you outfit your tank the ilvl200 dungeons are a joke you should be able to do them all with practice. I am suggesting that you do this based on what I did and was thankful I did gear my tank up before I took my 4 other toons into the heroics. This saved me a lot of wasted gold on repairs and a lot of cursing at the screen! Once you get the tank going concentrate on your healer next and lastly the dps. The older herics have been nerfed a bit too so you should find success fairly quickly.