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.
Island expeditions - Set sail for the previously unmapped isles of Azeroth. Battle in groups of three as you race against cunning rival intruders—or enemy players—to collect the island's resources. Constantly evolving challenges await as you traverse frozen landscapes near Northrend, open the gates of an abandoned Gilnean castle, navigate a war between elementals and more. Can be done either in PvP or PvE against advanced AIs.
You can try joining a Discord server themed around the class you’re playing, how you like to play World of Warcraft (achievement hunting, dungeon-running, player-versus-player combat, etc.), or your location, to name a few examples. World of Warcraft also has player communities built directly into the game. Find a community themed for newbies, or whatever else you want, and you’ll have a great resource to go to with questions. You might even make a few friends (or fellow adventurers).
Eventually, the Alliance finishes its preparations and launches an attack on the Zadalari capital of Dazar'zalor, their goal being to sever the budding alliance between the Zandalari and the Horde by dismantling the Golden Fleet and capturing King Rastakhan. Despite Anduin and Jaina's desire to capture him alive, Rastakhan is overwhelmed by the power of his pact with the Loa Bwonsamdi, and the Alliance champions are forced to slay him. Enraged by Rastakhan's death, Horde champions launch a vicious counterattack on the withdrawing Alliance forces, which ends with both Jaina and High Tinkerer Mettatorque gravely wounded. As the Alliance leadership debates their next move, Sylvanas, infuriated by the Horde's defeat, resurrects Jaina's long dead brother Derek Proudmoore as a Forsaken, an act that horrifies the surviving Horde leaders, with the intent to use him as a sleeper agent to destroy the Proudmoore family from within.
Set sail for the previously unmapped isles of Azeroth. Battle in groups of three as you race against cunning rival intruders—or enemy players—to collect the island’s resources. Constantly evolving challenges await as you traverse frozen landscapes near Northrend, open the gates of an abandoned Gilnean castle, navigate a war between elementals and more. Tides of Vengeance adds two new Island Expeditions to the mix and two new random events, as well as updated rewards.
These guides are completely automated and work in-game, so you can see step-by-step instructions as you play. The guides automatically move to a new step as you complete the quests. You are told where to go i.e. the questgivers for accepting and turning in quests along with where and how to complete the quests. Zygor has more steps and details, which would be more suited to beginners. Dugi condenses the info into fewer steps, but still has all the necessary questing info.
It’s a good thing that the previous expansion, Legion, was the best in the game’s history because Battle for Azeroth is coasting on its success. The major class redesigns that happened then remain in effect (though some are a little worse, and some a little better), and the combination of World Quests and Mythic+ dungeons means there’s always something to do, no matter your skill level or how long you can play.
Anyway, however you choose to get to the addon's menu, choose guide list and then pick the zone you want to quest in. There are some zones that will autoselect based on quests in your log, but not all guides or all quests are set up that way. (If you don't want to switch to a guide that auto-pops up choose "not now" or "never") As you can see in the screenshot, there are various categories of guides. Most max level content (such as Argus) is found in Achievements rather than leveling.
Dugi’s leveling guide is the leveling addon I’ve always used to level as fast as possible. It will show you where to go and what to do in-game, speeding up the leveling process. This is optional though, as the game already does a pretty good job at showing you where to go at all times. The addon does, however, come with a couple of other nice features and perks.