AWESOME spot.. if you are a druid, here's why.  This spot takes place on an island in the very north part of Stormheim, which is surrounded by water.  In this water are 2 groups of crabs that roam in packs of 12.  Each of these crabs can be skinned for scales and with the usual perks I mentioned in the earlier skinning spots.  (See spot 13).  The only catch is sometimes the crabs are very far apart and require some travelling to get to.  Druid travel forms not only have increased swim speed, but the wild charge ability allows you to swim 150% faster for 10 seconds, all the while replenishing your breath meter.  Pretty cool right?  I found that druids are AWESOME for farming this spot and can easily outclass other farmers here.  It's a druid spot that limits the competition – while ensuring you have the most uptime.  Very cool.  Gutting and level 3 stormscale skinning recommended.
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.
Even if you don’t have flying in WoD be sure to get the WoD handy notes. If you have flying simply fly and pick up all the treasures that you can and do bonus objectives. Not every single piece of treasure will be worth it though as some are hidden in caves or are just hard to get. So if you find yourself spending more than a few minutes finding a treasure, just skip it and move on, there is plenty of treasure to go around.

Be aware of the seasonality of items. Check what items are used in seasonal achievements, such as Delicious Chocolate Cake or Small Egg during Children's Week. When the Darkmoon Faire is in season, Darkmoon cards and decks (Furies, Elementals, Lunacy, etc.) tend to sell well, but prices also tend to get depressed. When the Faire leaves, prices return to normal, but sales volume decreases. The same is true of things like Snowman kits, Red Holiday wear, etc. Holding onto that Snowman kit for a few months, and then listing it in July, can net you a significant profit.
That being said, there are occasions when a little kindness is not unwarranted. A typical example is a new player who just dinged level 20. They are suddenly confronted with a whole set of relatively expensive skills at his or her class trainer, and the cost of mount and riding training, and needs a small amount of money to learn those new skills. Likewise, sometimes one sees a player who, just by the way he or she walks, is clearly a new player. Kindness to non-whiny, well-intentioned, legitimately inquisitive newbies is karmically rewarding, and one should not worry about shelling out an occasional boon to such players. Remember, at that level, a few gold can go a long way. Heck, even a few older bags that you have lying around collecting dust in your vault will often be much appreciated.
Despite all of these problems and this laundry list of glaring systematic issues, the crowning achievement of Battle for Azeroth’s endgame is that it still remains enjoyable all due to those two pillars of raiding and dungeons. That won’t last forever. As the expansion goes on, and the grind necessary to progress becomes even more demanding and the time spent in content that simply isn’t fun increases, it will be harder and harder for raiding and Mythic+ to carry the expansion along.
Herbalism is also a good source of money. Herbs are required by alchemists and scribes. Unlike ore which is found only in rocky areas, herbs can be found in many places. Be sure to check on the auction house for what herbs are in demand for a high value; often a lower level one is very valuable, so you can farm an area you already know for quick money.

The Horde 12-20 (Barrens + Stonetalon Mountains) guide has been rewritten and revamped.  In addition, there has been numerous tweaks to the speedrun route to make things faster and easier to follow.  Also, in case you haven't noticed I am now adding about 40% more info per step and redoing all the images.  Unlike with my previous vanilla guides, I am now giving a brief explanation of where to go and what to do with each step along with any other helpful tips.

The old popular example was the This item differed on my server from a high of 6k to a low of about 3k. When the price was down at 3k, I would buy a few of these and just wait a week. Throughout the week, I would put in trade and the auction house that I wanted 6k for it. I would then immediately go onto an alt and say that I only wanted 5200g. Sometimes, I would get the 5200g and be a very happy man, other times it would take more patience. However, almost always, by the end of the week, the other sellers had reposted for around what I wanted. This gave me a huge advantage. Now, the price ceiling was no longer 3k on the auction house, but 5k. I could now easily sell the few I bought for 4 or 4.5k, which is a huge 50% profit from the 3k I originally invested.
Combat is turn-based and there is no time limit on each round in a PVE Pet Battle. You can take your time to determine which spell to use next. Some pet abilities have multiple round cooldowns, while others can do extra damage if certain conditions are met. Be creative and have fun testing which combination of attacks works best against different wild pets!
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.