First of all write down all organic chemistry reactions, important concepts & some solved problems which consist of those concepts on a piece of paper. It will take time so I suggest you to do it on weekend. After that you just have to give an hour a day to revise them DAILY! Only a hour not more than that because you have other subjects too. So by the time exam comes you have revised conceptual chemistry for 'n' no. Of times. & You can prepare inorganic chemistry prior to the exam.