Bite size chunks...
A little and often is often more productive than an intensive study session
What is your learning style?
How do you best learn - are you a visual, auditory, kinaesthetic or tactile learner? Knowing 'how' you learn is the first step towards effective learning
Plan your time
Find out when exams are, plan ahead but remember breaks are important too - short intensive sessions when you are feeling fresh are more productive than longer less intensive sessions when you are tired.
Take a break!
No-one can study for very long periods of time - include rest breaks in your study timetable; time to switch of from study and enjoy yourself is important though make sure you don't spend the whole time relaxing!