If your 'light' revision before was actually light, then you definitely can. The key thing find is to focus on testing and exam practice. Exam technique can often be important enough that it raises you a grade, so practise past papers, look at mark schemes and do timed questions.
And then for testing - this is so much more effective that reading revision guides / making notes, and will help you remember masses more in exams. I find it useful to just create my own quizzes (flashcards, pop quiz, longer questions, using textbooks etc) as I read through the content, and then I return to these pretty regularly (weekly usually) to see where the gaps are in my understanding / what I'm forgetting. There are also some useful websites for it - Seneca Learning is great, quizlet is decent. and there are more but those are the best free ones I've found.. Good luck!