Ive said it a few times before but the best thing I did when I hit 80 was to level JC on my tank and get the crafted trinkets and stack a bunch of stamina gems in them, also the dragons eye gems are nice. This bumped my health from 21k to 25k, with 25k being in my opinion the ideal number to start tanking heroics. I managed to get first boss in Cot down with 21k health with some hard work, but when I went back with 25k health I easily 1 shot the rest of the instance then cleared Gundrak, and Uk only wiping a couple of times to the elemental boss in Gundrak.

Here is my tank for reference http://eu.wowarmory.com/character-sh...+Mill&n=Hoebag

Dont copy my tanking spec though because I messed it up