Advice when it comes to revision

I’ve started year 12 and obviously im trying to build good study habits from the start and that also means reviewing/blurting and revising content consistently. At first for the first few days it was going well but id slowly become tired when I woke up early to do work and not revise and get distracted in my frees. Does anyone have any advice on how to avoid this and maintain motivation? I do biology, chemistry, psychology and any advice is appreciated.