If you are just coming out of Level 110, you will probably have a number of different Legendary items to choose from. Your Legendaries' special effects will stop working at Level 116, but until then they can be a very powerful addition to help you level up quickly. These are our Legendary recommendations for leveling as a Marksmanship Hunter in Battle for Azeroth:
The Heart of Azeroth is an artifact given to the player character from the world soul via Magni Bronzebeard. It is a necklace that can use the power of Azerite, the lifeblood of the embryonic titan Azeroth (See Plot, below). Azerite is similar in function to Legion's artifact power, in that it is gathered normally from playing the game and is used to upgrade an artifact; likewise, the Heart is similar in function to Legion's artifact weapons by having the capacity to be constantly upgraded. Unlike artifact weapons, however, the Heart is shared with all of the player's specializations and can empower all eligible pieces worn simultaneously.
After identifying items that people want you need to figure out how to obtain them at a lower price than the current auction house price, as this will ensure a profit. In general there are three ways you can obtain items in the game: buying them off the auction house, looting them (from mobs, nodes or similar) or crafting them. These methods help you obtain the items that you want to sell. This leads into the three main gold-making methods in WoW. Crafting, Farming and Flipping. So let’s dig into them.
After completing your island expedition and second foothold, head back out to your third and final zone to quest in. Note that any legendaries you were using to level have become inactive and are merely stat sticks now. Feel free to replace them with quest gear as you obtain it. Before heading out, feel free to send your three champions out on new missions!

Professions: This may seem strange for a leveling guide, but the first opportunity you get, pick up both the Mining and Herbalism gathering professions. Not only will this allow you to track many various quest objectives on your map, but you also get a fair amount of experience whenever you gather. I'd put it at around 10% of a quest turn-in per gather. Since most of your wasted time in WoW is travel time, stopping to gather ore or herbs can keep your exp/h rolling as long as you don't go too far out of your way. You should only gather if it's convenient, and on the way to an actual quest objective. Don't make gathering your priority. 

Once your character makes it to Outland and beyond, cashflow frees up considerably. The quest rewards are much better than in Azeroth. In fact, a typical character will earn from 1000-1200 in quest rewards and vendor trash while leveling 60-70 in Outland, and perhaps 1400-1600 from 70-80 in Northrend. The tendency is, therefore, to spend more freely after one hits 60. However, it is important for players not to go crazy on their spending once they make it to Hellfire. One thing is, training costs, repair costs, and consumable costs are also higher. More important, there is a large purchase that you are going to want to make at some point after level 60, your first flying mount and skill. The "bird" costs 40, the skill will cost you far more. Not only that, but if you want to fly it in Northrend at level 70, you'll have to shell out another 400 for Cold Weather Flying. And for those characters who will be 'farming' herbs or ore in either Outland or Northrend, an elite flying mount is almost essential, as it helps you gather almost twice as fast. That's another 5000 you'll be looking at. Therefore, budgeting carefully during the 60-80 leveling process is essential to ensuring you have sufficient cash on hand for making those purchases. Saving your pennies early makes that bird appear that much sooner.
In Battle for Azeroth, the fall of the Burning Legion has set off a series of disastrous incidents that reignites the furious rivalry between the noble Alliance and the mighty Horde. As a new age of warfare begins, Azeroth’s heroes must set out on a harrowing journey in search of new allies, race to claim the world’s mightiest resources to turn the tides of war, and fight on several fronts to determine which side will lead Azeroth into its uncertain future.
The bones of Mythic+ are fairly simple, but it’s that simplicity that makes it Battle for Azeroth’s most rewarding mode. It’s fun, generally only takes about 40 minutes per dungeon and allows small groups of players to push themselves exactly as hard as they’d like. Battle for Azeroth’s dungeons are extremely well-designed and consistently entertaining, even after doing some of them 20-plus times, which makes the challenge of Mythic+ a great way to keep people playing.
For the purposes of testing this strategy, I started on a new server (High Pop), and the results have been very reasonable after only 3 weeks. I spent 3 hours farming ZF, 3 hours farming RFK, and then 1.5 hours average in WC the following 2 weeks. I currently have about 250 items up for sale, and have made an average of 20k per day over 21 days. Thats 420K gold over 3 weeks, for about 9 hours of work.

Rogues can make fast money from pickpocketing mobs, opening lockboxes and selling items that drop from those on the AH. If you don't have a rogue make one and get him to at least level 16. Rogues can also make some money by picking locks for people and getting tips. Not a great revenue source, but a decent one to supplement multiple strategies for making money. Generally, the usual lockpicking tip is between 50s to 1 gold, the most common being 50 silver. Sometimes, you can get lucky and have someone tip up to 5 gold for lockpicking several (or even just one) boxes. It's always beneficial for a rogue spending time doing repairing, training, etc. in a city to put up a lockpicking advertisement on the trade channel. Just make sure you let the buyers decide the price and that your lockpicking level is high enough.

The most simple thing is TradeSkillMaster. This AddOn shows you quite an amount of information in the items tooltip. In my opinion, DBRegionMarketAvg the best source. It tells me the price, an item was posted on all EU realms in the last 14 days. Why not DBMarket? DBMarket only shows you the items value from your server in the last 14 days. This value often gets manipulated. Some people start to post an item with a 500g value for 500.000 Gold on the auction house for several weaks. As a consequence, DBMarket is rising towards 500.000 Gold.  If you use DBMarket with 100% and post your item for 500.000 Gold, nobody will buy it.