With the best will in the world, forget making flash cards. Of all the revision activities you could spend your time doing, this is the least beneficial to learning yet so many people do it. Why - because it is easy and when you have created a stack of flashcards, you have something to show for your time, even if you can't remember what is on them.
If you want to spend your time productively, read through your notes after each lesson.
Note and attempt to learn key words and key terms.
Note and memorise key formulas and make sure you understand key concepts
Then, write your own exam style questions and answers.
Finally, get some past papers and answer topic related questions before checking the mark scheme to see if you got it right.
Now, you are probably thinking that that sounds like a lot of hard work and it would be easier to continue making flash cards? You are right. It is hard work and effort is required. You certainly can't do what I have suggested in front of the TV. But that is what A* students do and that is why they get A*s.
Good luck and don't waste any more time on flash cards.