There are a lot of players trying their hand at goldmaking. We all like to focus on quite different methods and ways to play, and this leads to a wide variety of playstyles that can work.
WoW is a huge game
There are so many items in WoW that it is impossible for anyone to be active in every market or know every little detail about which players may want or care about. Add this on top of the fact that players play the game in very different ways focusing on completely different gameplay activities and you get huge variations across servers and players.
What works for someone else may not work for you, and what works for you may not work for anyone else.
You can only learn from doing
You are the only one who can figure out what works in your specific situations, and the only way you can learn is by trying things out. As always I think the best way to find markets is to focus on finding ways to help other players become more powerful or look cooler. There are tons of ways to do this with crafting professions being my favorite one.
So test different things, record the results and stick to the methods that worked best for you, regardless of what worked best for others. No one, me included, can tell you exactly which markets or methods will be best on your realm, or for your playstyle. I can give you ideas, but nothing more. You have to execute them!
If it works for you keep going
Don’t let anyone else dictate what you do. If something generates a profit, and you like it, just keep going. Of course you may want to find more lucrative methods, at which point it can be a good idea to look around at what richer players are doing, but the motivation should come from you. Don’t change something just because someone else can’t get your results, or think the results aren’t good enough.