For my side projects I have a dev log and every day that I work on them I've gotten into the habit of writing "What I want to accomplish", "What I did", and "What's next", which all seems to capture my thoughts pretty well. I don't get super detailed on them, but I can look back at previous days to see what I should work on next and it helps me goal set better. Also helps me when I need to pause on my work for the day so I can pick it up later.