This guide is meant for normal server only. On my server the alliance out numbers horde on a ratio of like... 5:1. So what I decided to do was use their economy because the horde's sucks.
1.Find a market.
Mine happens to be tailoring so I make bags. I make imbued netherweave bags. Image of the Horde bag economy:
Imbued Netherweave Bags, Horde
Image of the Alliance bag economy:
Imbued Netherweave Bags, Alliance
Now you can see that the alliance prices of bags are much lower. So an idea is to buy the bags of their factions and see them to your own. This idea is basic but they are better ways to make some money.
2. Research the market.
So to make an imbued netherweave bag the mats are:
Bolt of Imbued Netherweave Cloth x4
Netherweb Spider Silk x2
Greater Planar Essence x1
Now selling the whole product is fine and dandy but look at the prices for the pieces of the product first to see if they sell for a higher price.
Just keep a watchful eye on which faction sells the most at the lowest price. Often times things don't seem right where as,you have more people therefore more farmers.
3. Supply and Demand
Netherweb Spider Silk, Alliance
Netherweb Spider Silk, Horde
Now as I said before my server has a very disproportional balance between Horde and Alliance. But from my research, the Horde has a lot more people selling their spider silk. There are a few variables that can explain this. One, there are more farmers than there are crafters on the Horde side. While the Alliance has a lot more crafters, probably because of the high amount of people, more people decide to craft their own items rather than buy them. Two, possibly many Horde player follow the same idea present in this guide already. Causing the amount of Alliance spider silk to go down and the Horde's to go up.
4. Race Matters
Greater Planar Essence, Horde
Greater Planar Essence, Alliance
Now the Horde has a higher price range on Greater Planar Essence for the most likely reason of having the Blood Elf racial with +10 to Enchanting. This upsurge in new players most likely gave them the idea to select Enchanting as a profession.
Arcane Dust, Alliance
Arcane Dust, Horde
Same Idea goes with Greater Planar Essence
And I forgot to add and too lazy to remake it. In order to get things across factions, use the neutral auction houses. I recommend Winterspring just because not many people are there as much as Booty Bay or Tanaris.
Hope you learned something about WoW Economics, if not you learned something from my Economics class...lol