I'm doing Medicin through time, Russia and the USSR, Cold War, and Henry VIII. My only advice is REGULARLY REVISE. History is now one of those subjects with a heap of content to get through so you cannot at all costs leave revision until the holidays or until a couple of months before the GCSE exams. There is simply too much. For those of you asking to do Geography or History: I took both and am a level 9 in both; in Geography, however, I got 96% on the 2018 papers in my mocks, yet in History I got on the grade boundary of a level 9. I would recommend Geography since the content is easier to learn and so long as you fully know the case studies and fieldwork, you will be fine.