This step is the most important of all. Reviewing work regularly strengthens the neural connections making memories stronger. This means you can recall information easily when it matters, most in the exam.
This graph shows what is happening to those neural connections with each review you do. We call it the Review Philosophy which is based on scientific evidence of how the brain learns and recalls information, otherwise knows as distributed practice.
Following the Review Philosophy means reviewing revision notes for ten minutes around ten minutes after writing them. A day later you review them for five minutes. A week later you review them for between two and five minutes, and the same again a month later.
Essentially, reviewing a subject in small chunks, several times in short bursts, has a far greater impact than cramming three hours before the exam.