What I did in the beginning was just to target specific bosses that I knew were easier and farmed for gear, and just progressively worked up from there.

I started with Drak'Tharon Keep, skipping Novos for a while. I soon graduated up to Gundrak and Utgarde Keep.

The biggest thing I did to prepare though, was that once my team hit 80, I started PUG-ing groups with my Paladin to collect Emblems and Gear, and learn the strategies for the bosses, that way I had a leg up when I started running them with my own guys.