If you queue as a healer - take care to always have a stack of water of appropriate level. You can buy it at an innkeeper for next to nothing, but remember that it will become too low-lvl for you very fast, so you need to buy new water every 10-20 levels. Alternatively, you can buy a stack of every tier of water in Stormwind, and just always carry it with you. Another alternative, if you see a mage - always ask him (politely) to create a table for you. Grab 2-3 stacks so you have extra for the next runs.
Bags: This SHOULD be a no-brainer. The cheap-o version are Netherweave bags, but if you have the gold I recommend you get the largest bags you can afford, since it means you won't have to stop to clean them out as often. In fact, if you have an excess of gold, it's probably not even worth your time to stop and loot mobs that aren't quest objectives. This seems like a small thing, but over the course of 100+ levels, all those clicks to loot add up.
Get exalted reputation with every faction you can. This relates to the previous two pretty directly. Gaining reputation with most of the factions of Kul Tiras and Zandalar will allow them to sell you high-level gear, while gaining reputation with the Champions of Azeroth faction will grant you levels for your Heart of Azeroth, the neck piece where all of your AP is stored.
As for the classes themselves, they almost all play like slower and slightly less interesting versions of their Legion counterparts. This is thanks in large part to the loss of one ability from each class that came along with Legion’s own AP dumping system: the artifact weapon, which added a unique ability to every spec in the game. The loss of these abilities left most classes feeling frustrating and incomplete, and though Azerite gear was supposed to be the replacement, it missed the mark completely. There will always be one Azerite trait that reigns supreme for each spec, meaning that the frustration of that particular loop will be unavoidable as long as the system is in the game.
Leveling used to be a treat in WoW. New, unique abilities drove you forward and made getting past the horrible grind worth it to some extent. Now it just feels like everything is set to grind. More than it used to be. Once it was tolerable, rewarding even, but now you grind to unlock an allied race through reputations barely connected to most of these races, only to have to level up that character to get their unique armor set (compelling you to not just boost your character and instead suffer through the slog of ANOTHER group of alts), then you get back to current content and grind some more with a random chance to drop the item you need to get your ilvl up to finally enjoy the single warfront available (as I write this).
You can also kick up your feet and watch your way through World of Warcraft’s story via Blizzard’s incredible cinematics—one of the company’s cornerstones. Sure, you’ll be spoiling yourself for parts of the game you have yet to uncover, and you might not know the importance of the various characters you’re watching, but you’ll at least get a pretty good sense of how World of Warcraft operates. Also, did we mention that Blizzard’s cinematics are gorgeous? We’d rather watch these than the Warcraft movie, that’s for sure.
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.
Players’ relationships with the NPCs around them have been hit-and-miss over the years. One of the original issues with Thrall, the Horde’s original Warchief, is that players began to refer to him as “green Jesus,” because of how infinitely powerful and infallible he was. But he’s been gone since the Warlord of Draenor expansion, and with the death of Varian Wrynn and Vol’Jin at the start of Legion, the old guard hasn’t been there to guide players the same way as it used to be.