Running instances at these levels is usually pretty difficult to do

Gearing Up: Disc and Holy Priests can use 12sky2 Gold the easy method of eliminating some gear choices by simply checking if it has +hit on it. If it does, it's obviously not a piece of gear that is meant for a healing class, it's not like heals can miss or anything. Even Shadow Priests can let some gear with hit on it pass to the Warlocks and Mages.

While leveling up and stick with it. Pick up gear relative to that spec, most of which will come from quests and drops from mobs from levels 1-60. Running instances at these levels is usually pretty difficult to do, and probably not worth your time.

Once you hit 60 you will gain a ton of rather nice green gear that will tide you over for awhile. Doing instances from 60-70 is much easier, and if you can get a competent group run as many as you can.

Be sure to check around the towns in the instances for any quests that may give blue items that are upgrades for your class/spec before doing the instance.

If you are not able to run any instances, quest reward greens and random drops from mobs will work just as well to get you to level 70.