This is a little thing I found while I was messing around on the AH, it has made me several thousand gold so far and I hope it will make you that amount too. Anyway, it helps if you are a Engineer and honored with the Ashen Verdict but this is not crucial.
Firstly, look at your servers Iceblade Arrows and Shatter Rounds and see what one goes for the most money. If it is the Arrows then you should buy all the Eternal Shadow you can. (Make sure it is no less than x5 the price of 1 stack of arrows) Next, turn them into Crystalized Shadows. Then you can either look for a engineer that can make them or just craft them yourself. Finally,re-list them the price you wish and eventually they will sell. (If on your server Shatter Rounds are the most money, do everything the same but you will be using Eternal Earth)
This method can rack me around 1-2k every few days from just 20 minutes of work, I hope it works for you too! (Amount made may vary depending on server)
(Sorry if this is a repost, have searched and cannot find this method anywhere)