I always write a README first for my projects, even when I am working alone on it. I also always create a Makefile, even if the project doesn't use make at all,

I always write a README first for my projects, even when I am working alone on it. I also always create a Makefile, even if the project doesn't use make at all, I know I can enter any of my project and hit make help to know what it is, and if I am browsing on gitlab/github, I can read the README. When creating the project, I put in the README a general description, project goals, a TODO list, contact info (email...), requirements (like node, ruby...). Often, I write the readme, and leave the project a few hours to a few days, when coming back, I read the readme and it should "enlight" me.