Plan far enough ahead of time that you'll be able to take a break and move away from the material at the end of each sub-section if you feel overwhelmed. Often time is needed to allow the mind to gradually absorb complex ideas. Read carefully and methodically, referring to figures and diagrams as appropriate. Draw your own diagrams or charts to summarize and translate information. Review your notes and the reading periodically.
Information needs to be reviewed and used periodically for it to be stored in long term memory.
Anticipate and practice responding to the kinds of test questions which might be asked.