Designate a place for studying. You should have a place set aside just for studying, where it is quiet and away from distractions. Make this area comfortable, as well as useful, by preparing the space with items you need to do your studying. You don't want to disrupt your study time by getting up to search for things you need.
Get plenty of sleep. Sleep deprivation can affect your memory, making it difficult to retain what you have studied.
Make a fixed schedule. Schedule your study time for a certain time of the day and stick to it. After a while, it will become a routine.
Take a break from your studies every 30 to 40 minutes to get something to drink or just to stretch your legs. This should be a short break, just a few minutes so that you don't ruin your concentration and get sidetracked.
Find a study partner. Often times you can get off-course studying on your own, but a partner can help you keep on track, as well as offer tips and ideas that you may not have thought of on your own.
Set definite goals. Decide what you need to study on that particular day and set a goal of how much you will try to cover. If you don't get through it all in the time you allotted, rethink how much time each subject will take and adjust your goals accordingly.