Special note: At 110 it's almost certainly worthwhile to go and immediately get your Heart of Azeroth and first piece of Azerite gear from the BfA opening quest. It doesn't take long and provides pretty high power levels. I'd then return to Legion quests until 111 or even 112, since the power of these items will increase your kill speed significantly over the scaled enemies of BfA content.
Special mention is the Darkmoon Faire Top Hat and WHEE! buff. While not always available due to the DMF being inaccessible most of the month, if you happen to be leveling when the DMF is running, it might be worth your time to go and get these. AFAIK they do stack with heirlooms, although I have not personally tested it. Fair warning: These buffs do NOT stack with each other, and the hats disappear after the DMF goes away later in the month(unless you only log in when the faire is running).
Dugi’s leveling guides cover everything from level 1 to 120, for both Horde and Alliance, and any race and class you can think of. You get an addon that you load inside the game which shows you step-by-step how to get to the maximum level in a streamlined fashion. There’s even a waypoint arrow that shows you the direction you need to go, so you’re always on the right track. The addon instructs you which quests to pick up, where and how to do them, when to turn them in, and even other features as well. Dugi guides have been around since 2005, so they’re probably going to be around in the future as well, keeping everything up to date and current.
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