On the marketplace you can't order anything but white armor or weapons at the moment. I tend to go with green on my armor and blue for my weapons when crafting them. I try to do better enchants to at least match, but found I've leveled fast enough it wasn't a huge difference if I had white enchants. They were better than nothing. I'm getting so I can actually craft some halfway decent enchants on my own, but haven't bothered ordering any good ones for my vet level toon.
So to get your gear from white to better you can either order the mats to do that on site and give them to the crafter making your stuff or see if they will just upgrade the items for free. For the moment you can note you want an upgrade. If the crafter is maxed out green and blue are easy to do. Purple and yellow are the ones that get more expensive, especially yellow.
This is a casual, mostly PvE player point of view. =) But definitely the higher up in color the better the gear. Just as a note, green crafted gear is usually pretty close to blue looted gear in the world of the same level.