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).
Warmode is one of the real stand-out features of Battle for Azeroth, even if it is a somewhat controversial one. Warmode tries to revolutionize world PvP like the game has never seen. By switching on Warmode, you enter a new version of your server with only other people looking to fight out in the world. The result is a more volatile world where fights can break out at any time, and groups from to go fight the opposing faction.
The best way to collect AP is through world quests, a system that allows players to complete menial tasks to earn moderate rewards. A finite amount of AP spawns on the map through these quests — generally at least 2,000 a day. I’ve likely done most of these quests close to 20 times in the course of preparing my various characters in the 45 days since the expansion launched. In some cases, I’ve replayed them as many as 50 times.
Alpha Beta PTR Classic 1.1.0 1.2.0 1.3.0 1.4.0 1.5.0 1.6.0 1.6.1 1.7.0 1.8.0 1.8.4 1.9.0 1.10.0 1.11.0 1.12.0 Burning Crusade 2.0.1 2.0.3 2.0.4 2.1.0 2.1.2 2.2.0 2.3.0 2.4.0 2.4.3 Wrath of the Lich King 3.0.2 3.0.3 3.0.8 3.1.0 3.2.0 3.2.2 3.3.0 3.3.3 Cataclysm 4.0.1 4.0.3a 4.0.6 4.1.0 4.2.0 4.2.2 4.3.0 4.3.2 Mists of Pandaria 5.0.4 5.0.5 5.1.0 5.2.0 5.3.0 5.4.0 5.4.7 Warlords of Draenor 6.0.2 6.0.3 6.1.0 6.2.0 Legion 7.0.3 7.1.0 7.1.5 7.2.0 7.2.5 7.3.0 7.3.5 Battle for Azeroth 8.0.1
You should try and quest efficiently - pulling several mobs if you can handle it, using your burst cooldowns while questing to kill everything faster. Many people would think that a 10-minute cooldown like Bloodlust is useless in open world, but you can do a "kill-15-mobs" quest in like 30 seconds if you pull a lot and use it. A free quest every 10 minutes is not that bad.

Footholds into enemy territories can be done as you grow in levels and should be completed before reaching Level 120. Take the time after completing your first zone to do your first foothold, or you can choose to complete one as soon as you gather your 100 War Resources which will prompt you to return to your mission table area where the first foothold quest can be obtained. Similar to how your initial zone selection was largely irrelevant, this selection is, as well. Simply pick one and complete it to earn your Mission Table second champion. Send your champions out on missions, recruit troops, and then head back out to quest in your second zone selection.
Island expeditions require groups of three players to venture to islands with randomly spawned enemies and piles of AP. The island expedition ends once they collect a certain amount of AP, and they are granted about 300 AP as a reward — unfortunately, players don’t get any of the between 6,000 and 12,000 AP they collect during the expedition. These missions can take anywhere from three to 20 minutes, and never once offer any real challenge or depth.
If you’d rather read than watch, there are also plenty of resources you can use to acclimate yourself to World of Warcraft, figure out what to do next, and ask questions when you’re feeling stuck. For the basics, we recommend reviewing Wowhead’s “Guide on How to Play World of Warcraft,” which is definitely worth scanning if you’re new to massively multiplayer online games or just want to get a sense of how Blizzard’s approach differs from others you’ve played.
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.
Unlock all of the traits in your Azerite Armor. Each piece of Azerite Armor — which can be head pieces, chest pieces and shoulders — has three traits that you can unlocked with Azerite Power, or AP. AP is something that most types of endgame activities will give you in Battle for Azeroth, but some are more effective than others. In the first few weeks, you’ll want enough AP to unlock all of the traits on all of your armor, however much that may be.
Allied races: Our new allies will join the factions and players will be able to unlock the ability to play their race. There are 6 planned for launch. Horde: Nightborne, Highmountain tauren, Zandalari troll. Alliance: Void elf, Lightforged draenei, Dark Iron dwarf. Additional races are planned for the future. Receive a Heritage Armor set, if you level an allied race character to level 110.[5][6]
Most heirlooms only work in a limited level range in their default form and must be upgraded to work at higher levels. That costs gold, and you’ll need around 30,000 gold to outfit yourself with a fully upgraded set (counting only those that give you bonus experience). You may need to spend some time on a boosted character to acquire the gold you need to outfit another character with heirlooms, but it’s well worth the effort.

If you love running old content for transmog items, you'll love the new legacy loot system. Whenever a player enters a dungeon or raid where they are 10 or more levels above the content, the dungeon or raid bosses drop an amount of loot equivalent to what would have dropped for a full group when the content was current. That means players could earn loot for five people in dungeons and loot for 20 people after soloing a raid. The legacy loot system also drops other gear types, like cloth dropping for a plate wearer. It's now much easier to get the transmog gear you want, and you can also collect gear for your alts on the same run.