My toon was a monk, a class that gets extra experience for an hour at a time. I picked at it more than I have in the past, so I benefitted more from the 150 percent "rested" experience bonus. If I wanted to run a dungeon for quests, I fired up a high-level character on a second account and dragged my little toon through them. And having leveled dozens of characters to 100 and 110, I knew every zone and every objective.
If you level with friends Prot would probably be the way to go so you could pull and face tank the packs. I leveled 2 pallies both ret on beta and had 0 issues. Selfless healer and wake of ashes work absolute wonders. I leveled a bit as prot and just felt like I did 0 damage. I leveled solo so I don’t know about the xp fall off but I would assume it’s the same as legion.
So, the initial leveling process is probably the longest it has been in an expansion in a long time. My first play through, it took me about 12 hours to finish every single quest in every single zone. Needless to say, due to leveling 7 times, my last leveling was done by a ret pally and took me just over 8 hours and completed every quest in the Horde zones. There are a few tips I would like to give for leveling in BFA.
“I’ve been a WoW player now since Beta and had a few toons that I always max leveled and played on a regular basis. I loved my other toons (have 1 of each class) but the quest/level grinds were beginning to get to me and soon they fell by the wayside of my play time. I started with Dailies and Events guide and once I started seeing how good the app was, I’ve never turned back and picked up all the Alliance mods. I’m now almost fully level 85’s with all my toons. Only 1 level on my hunter and 4 levels on my warrior until I’m done.
Skinning is a good money maker as throughout your travels you will fight many beasts. It also won't take much time, only 1-5 seconds after every beast. Miners and herbalists have to travel all the way to the nodes. Skinning also provides the passive bonus Master of Anatomy, increasing critical strike (which is especially helpful for agility-based characters who take it with Leatherworking).
I made one for my guildies but its for the Horde leveling process. One tip that goes for both factions is that you dont need to do all 3 zones to hit 120. I did like 1 and than three quarters of another. But once your 120 you need friendly with all 3 of your factions new reps to unlock world quests so make sure you hit at least friendly with all 3 while your leveling.