Revision is the key to good marks. Revise, revise and revise thoroughly. Since you have studied the entire year, you do not need to study further, but to revise. Even if you have some topics left to study, do not start a new topic unless you have revised all the studied topics thoroughly. Also, do not skip and revise. Revise at a go. Do not leave any topic for revising it later. Start from the beginning and revise each and every topic till the end, without skipping any topic in between.