To give you some perspective I leveled both a LF Ret Paladin and BE Rogue (so one started from level 20 and the other from level 1). I focused on getting the achievements I was missing for the Loremaster, so not the most efficient route by any means. I was using full enchanted heirlooms (minus the ring) and the WoW-Pro addon though, as well as having War Mode turned on all the way.
Though related, this is no longer true. You can now purchase a lvl 90 character boost. Some power levelers have hoped for a day when you could use real money to buy individual items in-game, some times called "micro-transactions." At a Game Developers Conference 2008, Rob Pardo gave a strong indication, Blizzard would not ever go this route with World of Warcraft.
En ce qui concerne la pièce d'armure contenant les améliorations d'Azerite, nous vous recommandons de prendre le Torse de Magni en premier. Si vous choisissez de commencer par Vol'dun, la première pièce que vous pourrez trouver sera un Casque, tandis que la dernière pièce seront des Épaulières. Cela vous donnera donc 3 pièces d'armure d'Azerite en quittant la première zone, ce qui vous sera d'une certaine aide.
Congratulations on reaching Level 120! There are a myriad of new things to do. The first thing you should do is head to your faction hub ship where you have been doing your mission table quests and footholds to pick up and complete the quests necessary to unlock World Quests. World Quests will provide you an opportunity to grind reputation levels, acquire gear, and gather Azerite. There are tons of new things to do that we will cover in our Level 120 Battle Guide found here: Level 120 Battle Guide