1. Keep in mind big themes.
2. Take notes as you read. What are the key ideas? What are the details of why and how? Can you explain them in your own words?
3. Re-read important content and examples to ensure you understand the material.
4. Write down questions for parts you don't understand.
5. Work through examples and try out problems (i.e., example programs in the end): do you understand why they work? can you solve them on your own?
6. Spend time understanding important figures and diagrams: what ideas, relationships, structures, operations, etc. are they showing? Try drawing them to help understand what they are showing.