Make associations between what you have just learned and what you already know. Take a break before going over the material again. This will give your mind time to work on the ideas and concepts. Read the material aloud. This makes two of your senses work at once.
Most people find it easier to read a bit at a time.
Shorten your reading sessions to between 30 to 45 minutes with a break in between. Shorter sessions throughout the week will be more useful than longer sessions. Find the material in another book. The way another author expresses an idea may help you to understand it better. Becoming a Master Student , Canadian Edition.