I know that the following guide is kinda common knowledge, but it is a very comfortable way to get 400-500g a day without a big effort and i just wanted to share something to you guys
The idea is to create items of the Savage Saronite Set (requires Blacksmithing 420-425)
Savage Saronite Battlegear - Item Set - World of Warcraft
Because many people level DKs and Retardins at the moment for pvping,
the savage saronite items sell very high.
For example:
Savage Saronite Pauldrons - Item - World of Warcraft Savage Saronite Pauldrons
The Savage Saronite Pauldrons require 12x Saronite Bar (average 1.71g/Bar) and 1x Eternal Water (average 7.2g/Item), which makes about 27.72g per Item.
I made the experience that you can easily sell them for about 100-120g, which makes an average 70-90g per item.
So all you have to do is to create some of the Savage Saronite Sets Items, put them in the auction house for about 100-120g.
Keep in mind that this guide is server dependent. I have no idea whether it will work on your server or not, but I made about 2.7k gold in 1 week doing nothing but buying saronite ore/bars and eternals, smithing those items and selling them.