Lets go farm for a while, leveling.

Many times there is a material that you are needing for a crafting profession. Well if it is something like mining or herbing you can do this on a lower level alt. This will give you some XP on the toon that you were playing any way. The reason you want to do this is it will help with the skill points gather mats and do things already you were going to do. Gathering is very easy with the add-on Gatherer to track for later. That way you don't have to go blind. I recommend this for all DPS classes. That way while you are waiting for those long times between Dungeons you can quest and farm at the same time. If you are a Tank or a healer I recommend getting skinning and Tailoring this way you can collect more skins and cloth for your main character that does the crafting professions. The reason for this is because as I have found if I want to play and instant queue character I will play a healer or a tank but if I want to just chill for a while and chat with my guild farm and do a quest or two.