They can help a speaker stay within the time limit.
They can substitute for a general lack of information.
They cover up a speaker's visible nervousness.
They help your audience understand and remember.
Rehearse with the person beforehand; introduce the individual to the audience just before his or her participation.
Never use other people as presentation aids in a speech because of the likeliness something will go wrong.
Ask for volunteers from your audience to help you on the spur-of-the-moment and act as your presentation aid.
Just use yourself as a presentation aid: with costumes, demonstrations, or illustrations.
Enlarge or project them.
put them in a large, attention-getting frame.
Make copies and hand the copies out.
Pass the actual photos around to the entire audience.
a line graph.
a pie chart.
a bar graph.