I keep really fine-grained and extensive todo lists. I helps staying motivated if you can just pick something small, do it in 10-30mins, and while checking your

I keep really fine-grained and extensive todo lists. I helps staying motivated if you can just pick something small, do it in 10-30mins, and while checking your todo item, you get the satisfying feeling that your project just got a tiny bit better/a tiny step closer to completion. This works for me even on days in which I don't have much energy or time to spare. Also, try to not let your project rest for too long, even if you just do the above-mentioned baby steps. I found that the longer I am out of it, the harder it is to bring back the motivation.