Reduce the number of slides. Meaning, go over the slides and determine which things will not appear on exam. If you have attended the lectures, it will be easier for you to identify things that will likely appear on exam. Plus, there will be things that aren't for writing questions (there is no way to write questions on these things). So using different techniques, identify things you should focus on. Know which things to memorize and which things you should ignore completely. Also don't try to memorize everything in one study..rather go over the slides once. And then repeat, repeat, ... and also don't forget to allot time for revising and doing questions.