What’s a good side job for substitute teachers?

I love being a substitute teacher. It gives me good practice for when I become a teacher and it’s a good job to have while I’m in school to be a teacher. However, it’s not really a dependable job. I never know what days I’m working and which ones I’m not until they’ve already passed. And I can only do so many hours a week while I’m focused on my studies. What’s a good side job to do while also substitute teaching and going to school full time? Especially for someone who lives in a rural area.