Studying + Revising A Levels

I just got my AS results back and they're not what I was hoping. I seriously want to pull up my grade in A2 cause clearly whatever I did the first time didn't work. I took English language, literature, and history and two of them were Bs 😭😭😭😭.

I'm supposed to have 4 A levels but we couldn't find an exam centre for French so idek if I'll take the exam atp and that means I'm so screwed cause my "safety" was AAB and rn i have ABB.

My original fallback plan was do seriously well in at least two subjects so if I mess up the other two I still have two As.

Pls share everything you use for studying and revising (e.g., websites/apps) and what methods work best for you. I need all the help I can get rn