Research instances appropriate for your level online. Running instanced content is the single most important thing you can do, at least up through level 85. Instead of focusing on questing, focus on dungeons. A quick search for “WoW dungeons by level” or similar will help you find the right instances for your level. Keep in mind too that many instances are faction specific, so make sure to check Horde or Alliance specific lists!
Created by Blizzard Entertainment and based on the Warcraft series of RTS games first released in the mid 1990s. WoW expanded on the early Warcraft single player franchise and is now a vibrant multiplayer online world, where players may engage in roleplaying, PvE, PvP, dungeon instances, battlegrounds, arenas, and raids. WoW has received four different expansions so far, including The Burning Crusade, Wrath of the Lich King, Cataclysm, Mists of Pandaria, Warlords of Draenor, Legion, and the latest expansion Battle for Azeroth and is still going strong with another expansion in the pipeline.
Most classes in World of Warcraft start at first level, but Death Knights and Demon Hunters are exceptions. They start at level 55 and 98, respectively. This alone can shave a huge chunk of time from your leveling experience. Of course, it only works if you want to play a Death Knight or Demon Hunter, but they’re both solid classics that can dish out damage or tank in a group.
I've been having what is apparently a scaling issue caused by inflated secondary stats on some Wrath of the Lich King items. In particular, my Highmountain tauren warrior leveled through Northrend and picked up a green, iLvl 87, 2h sword. All of the secondaries were in the +25 to +30 range, and the Dugi Gear Advisor decided it was better than the heirloom 2h axe I was using. So I went ahead and equipped the sword.
As late as possible. Early on, you’ll want to follow the missions in Battle for Azeroth right up until you get the option to send a follower on a two-hour long quest. As soon as you get there, stop doing the War Campaign missions. You can come back to them once you have reached something like 119 and a half and finish leveling with those if you want. If you don’t use these missions to cap off your leveling journey, then they’re the first thing you’ll want to do once you reach max level.