How can I improve from a C? History GCSE

So I recently did a history mock on medicine through time and got a level 5 (C). I’m pretty disappointed, I mean I’ve been putting in a lot of effort for history, all of last year I got 5s too and I’m just wondering how I can improve. My structure and SPAG is good and I’ve always been good at English, but I don’t understand why I can never get higher than a C. My marks were 22/32 and when I was going through it I noticed that on my 4 marker I got confused with preventive medicine and curing diseases, I also didn’t link back to the question on my last paragraph in my 12 marker. So I’m not sure if it’s that or something else. I talked to my teacher and she’s agreed to go through me mock and give my advice on how to get a higher grade like a level 6 (B) or a level 7 (A). But I also want to know from anyone who’s doing history at GCSE or has done it and got a high grade.