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.

In addition, you'll want to pick up leg and shoulder enchants and have them in your bags. These enchants have a level requirement of 80/85, but can't be placed on items above iLVL 136. You can get around this by having a level 85-100 character apply the enchant before mailing it to the character you're leveling, thus getting use of the enchants before level 85. I've personally confirmed that this works.

Anyway both got to 110 at around 50h played. I messed up with my Pal by going to Legion once I hit 100 instead of finishing treasures and bonuses in WoD. All in all, if I picked the best zones and was only trying to level as fast as I could, I would probably could have done it in roughly 40h. Note that it would have a been A LOT faster with a Monk as both Ret and Rogues don't really have a decent AoE until 40+ (45 for Ret and 63 for Rogue I believe). The daily also helps a lot. I know that leveling my Monk before the pre-patch was insanely fast. Might be slower with the changes to FoF, however.
The term “role-playing game” also means that you play the role of a character that lives in a fantasy world. How deep you connect with the character – is up to you: some people come up with habits, manners, and the whole biography of their game counterparts. Diving into the virtual world can bring a lot of fun, but the choice is yours – perhaps such a game style simply doesn’t suit you. This role component is voluntary, but we provide some role-playing worlds for those, who prefer to play with a full immersion in the world.

As you're leveling, I generally recommend you just follow the natural flow of the progression through each zone. They're laid out fairly reasonably. But don't be afraid to hop around, especially if you're near a quest objective. You shouldn't actually need ALL of the zones listed to reach 62. Pick the ones you like best. It's much more important to simply be as focused as possible and flow from one quest to the next.
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.
These stat priorities help to get a rough idea of what gear to go for, but the most important thing to get as soon as possible is your stat weights. Stat weights help you zero in on which stat is the most effective at increasing your healing. However, healers have no grand simulator, as there are a lot more variables that can affect your overall performance than there are for DPS specs. In light of that, healers use fight analysis tools like WoWAnalyzer and the Teachings of the Red Crane spreadsheet that takes logs from WarcraftLogs and gives you accurate weights that would improve your output.

The power of items depends on their item level, which you can see on the item's tooltip; the higher the level, the better an item will be. However, the Warforging and Titanforging system - introduced in the Warlords of Draenor expansion - means that almost any item of Uncommon, Rare or Epic quality has a chance to ‘forge' to higher than its base item level: Warforging is up to +15, Titanforging is up to +45.
Incursions are a new world content activity that are unlocked when one character has unlocked World Quests. This feature is unlocked account-wide meaning that all characters on that account can access Incursions even without being Level 120. This provides for a lucrative experience acquisition method that is available in a similar pattern to what Legion Invasions offered with nearly an entire level earned by completing an Incursion series which involves four World Quests and one mini-scenario at the end. These also grant item level 370 weapons and Azerite armor, so they should be done any time they are up. Incursions follow a similar schedule to Invasions and are available for 20 hours once they are initiated.
That lack of storytelling agency may soon change with Patch 8.1, Tides of Vengeance, which is coming to Battle for Azeroth soon. While there are plenty of fun gameplay changes that should make the expansion better, one of the most interesting additions is that of choice. In an upcoming quest, players will be able to choose whether they want to support Saurfang or Sylvanas — essentially honor or evil — in the struggle for Horde warchief.