Bags: This SHOULD be a no-brainer. The cheap-o version are Netherweave bags, but if you have the gold I recommend you get the largest bags you can afford, since it means you won't have to stop to clean them out as often. In fact, if you have an excess of gold, it's probably not even worth your time to stop and loot mobs that aren't quest objectives. This seems like a small thing, but over the course of 100+ levels, all those clicks to loot add up.
Avatar – Avatar over Deadly Calm. Deadly Calm seems great until you use it and realize the spells you would like to spam either have cooldowns or don’t even cost rage. It mainly allows you to spam Slam for 6 seconds but I usually have enough rage to spam Slam anyways. On the other hand, Avatar’s 20% increased damage is always reliable and useful at anytime.
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.
The level cap represents the ultimate goal and culmination of the leveling process, with max-level characters having gained access to all class abilities and talents, and being able to access end-game content and equip the most powerful gear. By providing an equal limit for the progression of all characters, the level cap allows for competitive and balanced gameplay in both PvE and PvP.
Level with a pet if you can because it will help keep you safe. If your pet is tanking all of the damage from the enemies you’re fighting, you won’t have to. The other reason is that pets are easier and cheaper to heal than you are. If you don’t have a pet, make sure you know how to use your defensive abilities. You can’t level quickly if you are dying all the time.
Special note: At 110 it's almost certainly worthwhile to go and immediately get your Heart of Azeroth and first piece of Azerite gear from the BfA opening quest. It doesn't take long and provides pretty high power levels. I'd then return to Legion quests until 111 or even 112, since the power of these items will increase your kill speed significantly over the scaled enemies of BfA content.
Edit 20 It’s been a week since this post and a lot of people are still reaching out to me with questions which is fine. I have had a few different people reach out to me to help make YouTube videos based off this guide and more info in BFA which I’m more than willing to do. Whoever gets the videos up first I will link them here for you guys to enjoy.