I’m currently predicted 4A*’s for UCAS so I hope I may be a suitable person to answer this.
The only main piece of advice I would say, is just to make sure that you are on top of everything. I know everyone says this but what I mean specifically is that there should be no instant where there are certain topics in your subjects that you do not understand (if there are, then address them immediately). It’s completely ok if right now there’s topics that you don’t remember and haven’t learnt off by heart, since you haven’t revised it yet, but just make sure that you have understood the content well in class so when it does come to revising, it’s a lot easier and you don’t have to spend time first understanding and then memorising.
Also this is a bit cliche, but if you’re doing subject like maths or sciences, make sure you get enough past paper practice in, after you’ve revised the content of course.