Simple, what is your studying routine after a day at 6th form or college, what helps you concentrate and achieve 'flow state'.
When I was at sixth form, the school day started at 8:30 and finished at 3:10. I stayed in the library after school until it closed at 4:30. Having small bursts of studying and breaks. I know if I work hard for like 20 to 30 minutes, I know I would have a break. More motivating than one big block of studying