I schedule things. I happened to use google Calendar, but the choice is unimportant. Block out time as busy: work, commute, gym, cooking, eating, sleeping, whatever. Pick the amount of practice needed for the desired target activity. It's quite clear when you can't add something new, and it's clear from progress in things when you need to shift. Some things take less to maintain than others.

It also makes doing things you want easy, and helps build habits. "Willpower doesn't work, habits do. Motivation doesn't work, planning does." is true in my experience.