Some people have made arguments that quest blues can sometimes be more powerful than heirlooms, especially with sockets. I'm not convinced. The simple fact that you never have to even look at quest rewards will save a non-insignificant amount of time over the course of leveling. Also of consideration is the value of enchanted gear never having to be re-enchanted.
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.
“It’s challenging for sure,” said Cobo. “but I think that, ultimately, we have to look at what’s at the core of the faction [...] Everything is about honor when it comes to the Horde, and as the story unfolds and you start to learn about the motivations behind Saurfang, or the motivations behind Sylvanas and why she’s doing what she’s doing, it starts to create a perspective around, ‘Is that the kind of person that I want to follow?’
This week, the story began: A short series of quests begin to pit Alliance and Horde against each other, and the skirmishes over territory that will soon be destroyed began. Realistically, that meant players had about 20-30 minutes of questing, at which point (without any in-game announcement or breadcrumbs) four world quests opened up in an existing contested zone.
The world quests aren’t necessarily bad, but they aren’t good either. I wouldn’t mind killing five of a type of monster or fighting one particular boss a few times, but after seven or eight, it starts to wear pretty thin. But going from levels in the mid-20s can take nearly 30,000 AP, so you’ll need more than world quests if you want to get your heart up in a reasonable time.
Isle of Quel'Danas: Special mention. At lvl 70 you can start doing the dailies here. Despite not being able to fly, the quest density is VERY high. I recommend hitting this every reset if you spend more than 24 hours REAL time(not /played)in the 70-80 level range. In fact, if you're doing a monk and only logging in once each day anyway, IQD WILL be your best exp/h for this level range.
Azeroth paid a terrible price to end the apocalyptic march of the Legion’s crusade—but even as the world’s wounds are tended, it is the shattered trust between the Alliance and Horde that may prove hardest to mend. As this age-old conflict reignites, gather your allies and champion your faction’s cause—for Azeroth’s future will be forged in the fires of war.
The way Zygor's works is there is an addon called ZygorGuideViewer that is just a UI addition that displays whatever guide you pick (which doesn't have to exclusively be Zygor's Guides). Granted, it offers some other cool capabilities like auto accepting & turning in quests and selling greys, but these are features that other addons can do as well. ZygorGuideViewer works within the bounds of LUA, which makes the addon itself (and therefore its use) "legal".
Buffs. Food/Flasks/Scrolls/Potions/Elixirs are a small, but noticeable, buff to your killing speed and survivability. If you have a max level character that can already supply you with cooking or alchemy, you'll be very well off, because the AH is a cesspool for this. I can't really give you specific foods or potions to look for, since each AH is going to have different supplies. Generally speaking, lower level foods are going to only last 15-20 minutes until you can buy the more powerful versions at 60+. Look for anything that adds versatility or your primary stat, and buy stacks for each level range(1-60/70/80/90/100).
For Alliance it's Lok'Modan, Redridge, Darkshore, Felwood, Stranglethorn (both parts), Plaguelands. Somewhere between 3 - 3.5 of these get you to 60 in like a 16 hours /played, if you queue for dungeons at the same time. I recommend dropping everything at 45 and going to Darkshore-Felwood if you didn't do them yet - they are literally the fastest levelling zones in the game right now, maybe only trumped by Silverpine.
But compare that with BfA's lackluster prepatch. Last week, players' uber-powerful Artifact weapons, which they had spent the entire Legion expansion building up, abruptly burnt out with no in-game explanation, no storyline, no quest, no Dad jokes from Khadgar, just a line of text on the Artifact screen saying they had been sacrificed to help stop the destruction of the world--part of the ending quests for Legion.
Dugi’s leveling guide is the leveling addon I’ve always used to level as fast as possible. It will show you where to go and what to do in-game, speeding up the leveling process. This is optional though, as the game already does a pretty good job at showing you where to go at all times. The addon does, however, come with a couple of other nice features and perks.