Answer:
Don't have too many cards, if possible; always be sure and number them.
Step-by-step explanation:
Having too many, and unnumbered, cards may end up in a problem. This happened to Sandy (she had too many and they fell so she got lost). Cards should help you remember what you need to deliver during the speech so you don't want to have too many. She had statistics and direct quotations but maybe you don't need 15 of them. On the other hand, you should always number them in case you get lost, you need to go back and repeat something, or, obviously, if they fall.