I've had a few different people ask me about my process for using 3D and for painting low resolution scenes, lately, so I've been sharing a basic step by step of this recent tribute to Heaven's Vault that I drew. I'm posting it here so that I can link people to it whenever they ask.
Step one is to gather reference files. Especially important because I'm paying homage to someone else's vision, and I want to try to be reasonably accurate. I have a mix of screenshots, concept art, pose references, anything that I think might be important. I use PureRef for handling my reference images, a wonderful free tool that I recommend to everybody working with reference material.
From this point on, it's just careful painting work, tweaking colour values, adjusting things for balance, and constantly checking my reference when adding detail to things like the ship and the buildings. Very few secrets here, just painting to the best of my ability and patience. Eventually I reach a point where I'm tired of painting detail, and any further painting is just fiddling, and I call the piece done. I then like to wait a couple of days, just to catch any stupid mistakes that I made because I was tired of working on the piece and rushing to get finished, and then it's finished for real. As soon as I show it to everybody, I notice all the mistakes, and vow to learn from these for next time.