Like many students I find it hard to revise. In fact, despite being boring, procrastination seems to be the name of the game we play. Exams, for me, mean that the act of learning additional stuff as recreation is not productive to the topics that exams are on. I find that even just reading a book pushes, what is sometimes more interesting, information into my head. This doesn't help clarify revision I undertake, in fact it seems to cloud all the definitions, acronyms and relations I've made with my every day life following the advice from Nathan Ghan's audio book: How on earth do I get a first? By getting: D.R.U.N.K: Define, Relate, and Use New Knowledge.

Using this method I go through module notes and slides and find all of the keywords, acronyms and concepts. List them, then write short definitions for each, where possible. I then try to think of an example of it's every day use in a wider context than in the lecture. After I have done this, if I can summarise the keyword with one other word not directly related to the subject, but with a strong enough link that I can reach the keyword without too much trouble.

One of my lecturers has spoken about the human ability to retain information and facts over a 3 day period. In their experimental psychology they discovered that the mind forgets 40% of information learnt over a 24 hour period. As such revision weeks in advance of exams, although useful, would possibly be complete to the desired standard for sitting an exam. The duration of revision is also a factor for knowledge retention. After a 90 minute period of revision the ability to retain information drops to 10% - according to a lecturer I have.
  
The act of compressing notes in this manner helps me to retain the information, not for longer, but with greater ease. Next year I intend to do this from the off. No more leaving it until exams are approaching. Hopefully it will be knowledge which I retain for the majority of my working life, and in this field I hope that it stays relevant despite the ever advancing state of technology.