Each method will make you wow gold. Skinning, mining and herbalism sold through the AH can all be very profitable. Many players do a combination of two gathering skills to make money. However, you can also do well with a creation/gathering combination. Probably 90% of all items made by trades are useless and will never be able to be sold to other players. I suggest you click on each item on the site and see where it's AH prices are listed as and concentrate on those items with the highest prices.

Gather the ingredients yourself to make wow gold. This may mean devoting a couple hours a week to just running around and finding herbs or ores, but it is worth it over buying raw ingredients from other players. Use our object maps to see which zones have the most spawn points for what you need to gather and then milk that zone in the game's off hours if possible. Then make and sell the items. Except for something like healing and mana potions, you are better off only putting one of each item up at a time. Keep in mind other crafters are putting up similar items and more items for sale generally means lower prices. It's in everyone's best interest not to flood the wow gold market. If you devote several hours a week to crafting, you can make quite a nice wow gold off of it over time.

The key to playing a creation/gathering trade skill well is to learn what sells and what doesn't. Except for particularly rare items for more wow gold, no buyout usually means no sale. Figuring a buyout is tricky. I generally use the rule of 3 times the recommended base price for greens. Blues and purples are pretty much sky's the limit. If nobody buys it, you can always list it again. For white items, check if any others are for sale and use that as a reference.