Different study techniques work for different people, find out which study method has best suited you over the years. For maths the best thing to do is to work through as much questions as possible, (ie. textbooks, past papers). This helps to implant the concept and understand it in your head. In English practise writing essays and develop writing skills.
For the rest of your subjects you can try just spending 5-10 minutes reviewing what you learnt in the last lesson and then making a summary sheet ticking off syllabus dot points as you go along. Alternatively some people find it effective to study in a group, so grab a few friends and test each other after each topic.
I found an article the other day with a list of different types of learners.
Visual learners: Visual learners learn by written text, they are usually good at reading.
Auditory learners: Learn by listening and like to talk instead of write.
Kinesthetic learners: Learn by doing it physically.
I am more of an auditory and visual learner. I also find that I learn while helping others.