Basically you just start at the bottom and work your way up. >_>
I did every instance multiple times through northrend. Did all the level 80 instances to gear up for heroics around 78-80. Then worked on the easy heroics like Nexus, UK and DTK. I actually healed 10 man Naxx about 2 hours after I hit 80, with two healers. It wasn't that difficult, had a few mana issues, but you just have to drink every chance you get. If you can manage to get into a 10 man Naxx with 3 healers, I'd do it. It's cake and the best way to gear up.
XI Wiki



