Revision is a skill, so knowing how to revise and how to make the best use of time is crucial. Here’s some sites with good general advice aimed at degree level students:
• Revising for and taking exams – brief tips and hints
• Passing examinations – revision and exam technique
• How to demonstrate your learning
• Revision strategies and coping with exam pressure
• Study skills notes from Cardiff University and something amusing if you’re in need of a break.