Stormheim is the zone you want to start it. For some reason Legion treasures are not worth any experience like they are in WoD...except in Stormheim. I haven't been able to find out any reason for this, and it's possible it may get fixed/nerfed at a later date. But for the time being you REALLY want to jump from treasure to treasure to augment your quest experience.
Blizzard has taken steps in recent years to smooth out out the leveling experience — Legion allows players to immediately boost one character to level 100, for instance — but if you want to roll multiple characters without spending money on multiple level boosters, you’ll need to spend time leveling. Thankfully, with the right maneuvers, it’s possible to level a character to 110 in a relatively short time. Here are some pointers for leveling in World of Warcraft, so you can rush through old zones and explore the new.
It’s a good thing that the previous expansion, Legion, was the best in the game’s history because Battle for Azeroth is coasting on its success. The major class redesigns that happened then remain in effect (though some are a little worse, and some a little better), and the combination of World Quests and Mythic+ dungeons means there’s always something to do, no matter your skill level or how long you can play.
Repetitive daily quests are a legitimate method of generating significant cashflow. Players who spend several hours a day doing daily quests can often generate 100 per hour. Many players have funded the purchase of their elite flying mounts solely through doing daily quests. Another trick for higher level players is to do level 70 dailies as a level 75-77. If you have a hankering to get a Netherdrake, for instance, and you already have a fast flying mount (which is a pre-requisite for the drake), you will find your mid-70s an ideal time to go get that drake. Not only will the quests be a lot easier to do at level 75+, but the dailies will pay about 1200 as you level rep, and you'll get XP along the way to boot (albeit not as much as quests in Northrend.) So if you're looking for a break from the grind of leveling to 80, and want to kick back, spank some level 69s and make some decent money along the way, doing lower level dailies can be a fun way to make some extra cash.
1 of my 3 polymorph tome spots. This spot requires a high level mage character (the tome will only drop for mages), and can also be done with the potion of luck for a quick boost to profits. Generally the kurzen monkeys in this spot have the highest chance to drop the Tome of Polymorh: Monkey – and the best part is they drop it often. Always check your AH before deciding to farm this spot. If theres not to many, then give it a try. In the video I actually got more than one to drop. It's the cheapest of the tomes, and consequentially the easiest to farm. Again, you MUST be a mage.
Island Expeditions are three-man scenarios that pit the team against three enemies using what Blizzard calls “advanced A.I.” That means the enemies will act more like players, pursuing goals proactively and filling class roles. The expeditions take inspiration from action RPGs, with randomized areas that mix up the experience each time. Players’ main goal will be obtaining resources more quickly than their foes, and expeditions should last 15 to 20 minutes. While primarily meant for PvE, there is a PvP mode that replaces the opposing A.I. with teams from the enemy faction.