Experience tells us that most ITC talks to well with between 15 and 25 slides. You have been working on the subject of your paper for months. What is perfectly clear to you must be made clear in minutes to people unfamiliar with your work. Your slides help you do this. Use your slides to hold attention, enliven, clarify, restate, explain, and interpret.
Ears have trouble accepting numbers and abstractions.
Quantities and relationships must be visually compared. By adding illustrations to your spoken words, you add understanding to what you are saying and enliven interest in your presentation. An outline of your major topics should be your second slide, just after the title. Trends - Line graphs show trends or correlations effectively. Comparisons and Proportions - Bar graphs are best for comparing magnitudes.