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.
Void elf - "Many have sought to harness the corruptive magic of the Void. Most who tried have fallen into madness. Determined to use this power for the good of Azeroth, Alleria Windrunner is the first mortal to succeed at defying the shadow's whispers. Coming to the aid of a group of her kin who nearly gave in to the darkness, Alleria has vowed to train these Void Elves to control the shadows within them and pledge their newfound powers to the Alliance."
If you've been away from WoW for some time, you may not know that the game's Legion expansion focused on powering up an impressive "Artifact Weapon" throughout the duration of the expansion. In short, players have been using the same weapon for about two years now. Artifact weapons were pretty cool and bosses did drop Relics which were used to upgrade them. But after two years of using the same weapon, many players are looking forward to the thrill of having an actual weapon drop off of a raid boss again.
Just like player item levels, the game's professions have become pretty bloated over time. Blizzard has made some updates to the leveling process before but Battle for Azeroth features a skill squish that should smooth things out considerably. Instead of having to level hundreds of points before you can start crafting Battle for Azeroth items, each expansion will have its own separate skill tier. In other words, you can start crafting Battle for Azeroth content right away, while the gear and items from other expansions will each feature their own separate counters. Your first Battle for Azeroth item will put you at 1/150 on the counter for the new expansion, no more grinding needed.
Also get the Heirloom Mount. Being able to have basic riding speed from the beginning will save you a lot of time if you're starting from level 1. Allied races start at 20, so this is a non-issue for them. It's important to note that Pandaren can not use this mount until they finish their starting zone and pick a faction. Being Horde or Alliance is a requirement of the mount.
Even though you will invariably do a bit of soloing during your time in World of Warcraft, the game is a lot more fun when you have other people to interact with. Whether you’re starting out, or getting back into the swing of things, having helpful mentors feeding you suggestions (or gear, or gold) doesn’t hurt. The /r/wownoob subreddit is a good place to find friends to quest with, as is the main World of Warcraft subreddit (and don’t forget its helpful “Murloc Monday” thread for newbie Q&A).
Valid pieces for Azerite empowerment are available for the chest, shoulder, and head slots of all classes. This equipment has multiple tiers of that can be unlocked, represented by a series of concentric wheels with icons representing individual powers; as individual powers are selected, they rotate into slots at the top of the interface, activating the selected benefit and locking out the others unless the player pays to reset their decision. Outer rings offer multiple choices, some based around the character's class and specification, others around the zone or circumstances in which the gear was acquired. The innermost circle offers no such options, instead being a boost to the level of the item itself, and thus providing a flat all-around benefit.
If you just care about unlocking the ability to fly in the new expansion, and you should, the site’s Pathfinder tool is a must-bookmark. Its Character Planner is also incredibly useful for getting a sense of what you could (or should) do next, based on your recent activity, the gear you’re wearing (and would like to upgrade), achivements you’re close to unlocking, et cetera. If you want a simpler guide, the site also has a great list of all the activities you should be doing each day and week in Battle for Azeroth.
Do quests and complete the story of your first chosen area before returning to your capital to scrap all of the equipment items you acquired. You should be around Level 113 by the time you complete your first area. Before selecting your second zone, head to your faction hub ship to acquire your introductory quests to the mission table and your champions. Complete this introduction and then pick up the quest to establish your first foothold in enemy territory.