Write note cards on index cards. Write main ideas on your index cards. Don't write details, or be stuck with the fate of looking down, staring at your note cards while reading. Put in some fun facts interactive questions, and other interactive activities on the cards to share with the class.
Write down keywords or main ideas. If you need to consult your index cards, you're only going to want to scan the index card for information, not read every last word.
Most of the time, the act of putting information down on your index cards will help you remember the information. So, while you might not strictly need the note cards, it's a nice security blanket to have if you happen to forget what you were going to say.