I just added a sheet of circle theorems. Unfortunately, you just have to learn these, but it’s well worth it.

You need to able to spot which theorem to use when you see a question. The best way to get better at this is practice. The more examples you do, the easier you’ll find it. Note that you may have to use more than one theorem in order to find a solution. Just take your time, mark on the diagram the things you know, like equal angles, equal sides etc. That should help you.