I have a particular fondness for graphic-design, so I have downloaded tools to make my own cover.

First I tried using Gimp, and wanted to build some props in reality and just take a photo of those items in good poses. However, this didn't match the aesthetic I was going for.

I always trust my partner, as their eye is very effective at sussing out what looks good and...less good. So I switched over to vector-graphics and delved into Inkscape. For the record, I highly recommend it - very effective and stable. Only issue is the learning curve, so be prepared to use Youtube alot if you're going to self-train on it.