I find all work in different fun levels. Also when it comes to drawing. If I have done a hard study, then I treat myself afterwords working on something I find more enjoyable. I like to have more than one project going at the time, so when I burn out on one, I can gain new energy from the other. I try to keep my workspace cleaned up. And remove potential distractions. (This is very challenging for me. How is this so hard xD )