While leveling, try to make use of the new Battle of Azeroth experience gem, Insightful Rubellite, which gives you +5% experience. Equipping one of these requires a socket in your gear, so try to hold on to a piece of Legion gear with a socket or acquire one of the Legion Legendary rings since every class has one. Each of the rings includes a socket. You can acquire one of these rings rather easily by doing World Quests in Legion zones and acquiring 1,000 Wakening Essences that can be used to purchase a legendary ring in the Legion version of Dalaran.
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.
WeakAuras 2 can be pretty complex and daunting for some players, but it’s another great organizational tool. It reorganizes buffs and status screens in a customizable way, so you can view them how you want to. It is a bit difficult and confusing to start these customizations, but thankfully there are templates that already exist for most of the basic customization options.
World of Warcraft offers a lot of ways to make money (gold). There is no one "right" way to make money, although there are some definite wrong ways! Some people like to play the Auction House, some people do their daily quests, some people tend to farm, etc. Many characters do a combination of all three of these along with other activities. Below is a compendium of money-making methods.

Making gold is all about finding the balance that works best on your server between all the above methods. When you find that balance, repeat, repeat, repeat, until you get the results you want. Never make any rash decisions without first consulting the economy. If you do not think you can make a for sure profit, then do not do it! Change only when necessary, because your clients become accustomed to certain practices that keep them buying from you even if under cutters offer a slightly lower price. If the customer is always right, then show that to them and you will be much more profitable!
From “The Burning Crusade” expansion, weapons like Klinge der Zauberei, Die Nachtklinge and recipes for different weapons are really valuable. The best example is Pläne: Teufelsstahlangschwert, worth 500.000+ Gold. These items are World Drops, you can find them in all raids and dungeons. I don’t know any Open World Drops, but that does not mean there are none. Another great transmog source are world bosses and rare spawns on Outland.