Have a transition activity after work to get yourself ready for your personal project. This could be yoga or a short run, or even meditation. Or a meal where you're not multitasking.

If you aren't taking classes, fix your after-work sked as though you have classes. Dedicate a night or two (or more) for your project.

Make sure you have time for leisure and other activities to avoid burnout or resenting your involvement in your project.