First thing you should do is to learn the market for the specific item you would like to monopolize. Let’s say it is Kingsblood. We can see a stack of Kingsblood is selling for 1 gold. There are 10 stacks on Auction House. To control the market, you have to buy out all the lots of Kingsblood, even single ones. Next move is to make auctions of Kingsblood you have bought for the price you want. Be reasonable and make it 2 gold. But all people are still being used to the old price of 1 gold and will not buy your Kingsblood at first. You have to maintain your auctions for 2 gold all the time, no need to put all Kingsblood you have at once, 3-5 lots are enough at the beginning. You can see, other sellers may start create auctions for 2 gold as well. That’s what we need. But if someone is selling for cheaper price, buy out their Kingsblood immediately. Soon people will start to accept your price of 2 gold as a regular price and will buy your stuff. Now you just to have to sell all Kingsblood you got. Control several markets. It can be anything, even twink blue items or items level 20-30 or 30-40. Same strategy works everywhere. It requires lots of time to track the markets and check auction house. It is not that easy as it may seem, you should spend at least a week of monitoring to be sure about prices, you will fail if you buy out everything at once without research. Soon or later, too many people will decide to sell your item as well. As they could see price change and think it had happened naturally. Market becomes overflooded. It is important to quit before the collapse. This always happens.
The simple truth behind all of this bickering and squabbling is that there really isn't a bad way to enjoy a game. You like the feeling of Classic taking you back to your young(er) days and that rush of falling in love with WoW for the first time? You like the slower pace of both combat and leveling? You like that the social aspects of the game take a front seat? Good, enjoy it! You prefer modern WoW and BfA with it's tons of improvements, smoother design and more player-friendly features? Great, enjoy it! It doesn't matter whether you prefer modern WoW or Classic or WotLK or whichever your personal high-point was (it was Burning Crusade and Legion for me), you're not wrong. You literally can't be. No matter what anyone says in all these heated discussions, they care about WoW, in whatever form they prefer it. So why can't this be enough of a commonality for us to have a civil discourse?