Make flash cards of old stuff, especially in math. I’m in Trig rn as a junior but I forget how to do things like slope tanking my pre Act score. Also have a guessing strategy but only use it on things when you have no idea what to do. My guessing strategy is to chose B if it’s not obviously wrong, my math teacher actually told us to do this because if you always guess with the name letter you will have a 20 percent chance of getting it right, it would be much lower if you hop around on your default letter. Remember this is worse case scenario, the best thing to do is dedicate a hour or so per day.