What subjects do you do? It varies depending on subjects usually
When I was studying for my GCSEs, I used various different techniques and found that some worked better than others for me.
I'm very much a visual learner, so listening to myself read the textbook did nothing. Because of this, I made all of my revision into both posters and into flash cards. Of course, I never actually used them, but the whole process of reading the textbook, condensing it into notes and then copying the notes onto flash cards and posters helped me to retain it. I used brightly coloured pens and highlighters to make everything visually more interesting (and a lot less boring to do!)
Also, instead of trying to learn the textbook word for word, I tried to really understand it, because that way you're able to put it into your own words even if you can't remember 'exactly' what the textbook says.
I did a lot of online research, too. I used MathsWatch for Maths help and I watched a lot of YouTube videos by teachers that went through past answers and highlighted the good and bad things. I don't know what you're studying or what exam board you are taking them with so it's impossible for me to give you links to 'helpful' resources - there's no point watching something about an AQA English exam if you're taking it with OCR! Just do a simple search on YouTube and you should find really helpful stuff.
Something I don't recommend - or didn't work for myself - is to 'revise with friends'. I always got distracted or talked about something completely irrelevant! I works for some people, but not me.
For exams with essays like English or Philosophy, I did loads of past essay questions and always badgered my teacher into marking them it's fine marking your own work, but I always find that really hard. I either mark myself wayyyy too harshly, or think 'there's literally nothing else I can put!!', so I think relying on a teacher's opinion is probably the best. After all, they do know what they're doing!
Hopefully this helped you even a tiny bit. Good luck with your exams!