Read the front and back of the book, including the inside of the jacket.
Flip through for pictures, diagrams or maps.
Check out table of contents.
Check for a glossary, and take note of the words entered there.
Read the introduction to each chapter.
Pay special attention to information inside text boxes, highlighted or off to the side.
Check for a table of contents as chapters may be named.
The first chapter is essential to the setting, introduction of main characters and perhaps even the conflict.
Skim through the beginning of each chapter.
Read the last two chapters completely.
Write out the setting, main characters, conflict and resolution.
List the ten most essential events that will explain the plot.
If you can't do something, return to the book to seek the answer.
Hope this helps.
I worked in education for many years.