Free tip to level up fast :
Join a HELPFUL guild. They will help you do quests faster and thus lvl up 10 times faster than grinding over night.
I was in a guild than noone was helping, and i was getting average 2 lvls per day by doing quests alone.
But, yesterday i joined some other guild, with ppl you can have fun with, and we did LOTS of quests with the help of lvl 80 DPS and 80 Healer.
It took us quite some time, but when i turned in 20+ quests, i leveled from 54 to 57.
Also it was so much fun running around with your guild in a dungeon.