Write it down.
I don't care if you use a fancy planner, a single page calendar you get from your teacher, or a piece of crumpled scratch paper you dig out from the bottom of your backpack. It doesn't matter.
List your periods in order (1-7, 1-8, whatever it is) and write down what you have to do (Period 1 - memorize monologue in drama; Period 2 - Page 135, 1-35, odd; Period 3 ---- (maybe it's P.E. or something and you got lucky)).
Write down everything so that you when you get home your plan is clear.
No. I'm not kidding.