This is a difficult question as people learn very differently. The main thing to point out about geography A Levels, no matter which board, is that they cover A LOT of content. It is possible to do it one year as any A Level is but you'd need to be dedicated to it. The content is usually straightforward but there are areas that people seem to strugle with such as the ITCZ etc. The triciest part of the course is able to manipulate what you know into answering the exam questions.
Once the content is covered, exam technique is key, the falling point for many Geography students is that they don't answer what is asked in the question. Often just stating facts and not going into enough detail and not providing the depth needed. So practice developing your answer and being synoptic as this is something students usually correct in their second year after their AS exams as you wont have this time.