This is something that helped me immensely while auditioning for Drum Corps. Once I realized that there were plenty of things I could practice without any materials I could turn any place or any time of day into my practice session.
I remember getting the Madison Scouts audition packet in 2012 and feeling completely overwhelmed with how much there was to learn. I not only needed to figure out how to play everything in it but I needed to memorize everything as well. I hated not being able to work on the way I sounded and having to simply memorize things during my valuable practice time. That's when I got the idea to try to memorize everything outside of my practice sessions.
Every day at school I would put my audition materials into one of my folders. Then while walking down the hall I would tap out the parts with my fingers on a notebook or my leg. If I ever "broke" while tapping, I would pull the music out and remind myself of what the part was. This seems so obvious but the reality is that by tapping through my music all day long, I simultaneously increased my comfort ability with the music and eliminated the necessity to try to learn music during my practice sessions. Every second I spent on a pad or drum was spent bettering myself as a player and not on memorizing music.
This is a strategy I still use today. Because it can be so difficult to allot time to practice, why let something like memorizing music get in the way of your ability to actually play the music?