GCSE OCR Geography A help!! xx

Hello, I took geography as one of my options but have found the step up from KS3 to GCSE very hard and I don't know what to do. I'm in year 10 at the moment and we're doing our extreme environments topic and have a test tommorow. We've done quite a lot of tests and I feel quite worried because I have only gotten C's and one (very low) B. In all my other subjects I am A/ A* so I feel like I should be in geography as well. If anyone has taken/ is taking this course how can I revise the information or learn it because I keep doing badly on the tests because this information is different to what I'm used to learning (it's all about processes and locations ) - how can I learn these things? Please help xx