But compare that with BfA's lackluster prepatch. Last week, players' uber-powerful Artifact weapons, which they had spent the entire Legion expansion building up, abruptly burnt out with no in-game explanation, no storyline, no quest, no Dad jokes from Khadgar, just a line of text on the Artifact screen saying they had been sacrificed to help stop the destruction of the world--part of the ending quests for Legion.
XP Potions: The Elixir of Rapid Mind and Elixir of Ancient Knowledge no longer drop. They can be bought on the AH still but are way to expensive for it to be worth it. The Excess Potion of Accelerated learning is available from your garrison quartermaster but only works for level 91 to 99. As of Patch 8.1 you can also buy the 10% XP Potion Draught of Ten Lands.
I highly recommend actually staying in the 20-60 range zones until you ding 62. The reason for this is that despite getting a slight penalty in experience for being over-level, the advantage of having flight will more than offset this. That, and WOTLK and TBC zones are the slowest part of the leveling process. Minimizing your time there as much as possible is worthwhile.
Professions: This may seem strange for a leveling guide, but the first opportunity you get, pick up both the Mining and Herbalism gathering professions. Not only will this allow you to track many various quest objectives on your map, but you also get a fair amount of experience whenever you gather. I'd put it at around 10% of a quest turn-in per gather. Since most of your wasted time in WoW is travel time, stopping to gather ore or herbs can keep your exp/h rolling as long as you don't go too far out of your way. You should only gather if it's convenient, and on the way to an actual quest objective. Don't make gathering your priority.
There are also a number of different online tools you can use to make yourself a better World of Warcraft player—and to help you decide what to focus on. Wowhead has a great Attunement Tool that shows you how close you are to unlocking significant milestones in the game, like unlocking new allied races, earning reputations with key factions (which will ultimately help you unlock faster mount speed and other goodies in the game’s expansion), and how far along you are in your dungeons and raids.
Zandalari troll (8.1.5) - "The Zandalari are a proud people whose origins date back to the early days of Azeroth's history. Their fierce warriors ride dinosaurs into battle, and they possess one of the most formidable naval fleets in the known world. But enemy attacks on their borders—as well as unrest within the king's council—have threatened the kingdom's foundations. By returning stability to Zandalar, the heroes of the Horde can gain a powerful new ally.."
Tiragarde Sound and Stormsong Valley are both fairly similar zones, but Stormsong is a little longer, meaning that you might not even have to finish it to hit 120. Tiragarde also comes with a bit of a warning. There are plenty of side quests to do in the zone after you finish the story quests. Don’t do them. It’s not worth the time or the experience you’ll get.