The right visuals can enhance and clarify your message, but the wrong ones can sink you like the Titanic, say the authors of High-Impact Presentation and Training Skills.

Too many visuals in a presentation, for example, can be confusing and tedious, while no visuals at all may seem boring. Computer-generated graphics in dozens of colors and type fonts can be overkill, leaving your audience seeing polka dots as they stumble out. Even worse is when equipment needed to run your visuals malfunctions, derailing your presentation altogether.

Visual aids are a necessary component of professional presentations and a host of other types of sessions. Certain audiences expect visual aids and judge your professionalism accordingly. But once the lights are dimmed, there’s also a danger of losing some of the personal contact that is essential to good presentations.

Ask yourself: “Will my presentation really be enhanced by visual aids?”

The answer is yes – if your presentation is instructional, or if you’re presenting technical or complex information. But if the purpose of your presentation is to entertain, motivate or inspire, you’ll want to carefully weigh the advantages and disadvantages before deciding to use visual aids. What you gain by using visuals in those instances may be more imagined than real.

The following “visual aid disasters waiting to happen” will help you sidestep the presentation mistakes that inevitably result from the ineffective use of visual aids.

Top 10 “Don’ts” for Using Visuals in Presentations

1. Don’t talk to the visuals — talk to the audience!
This is one of the greatest flaws of presenters. Even worse is to walk up to the screen and point a finger at the information. To indicate a specific point, use a pencil on the overhead, a pointer on the flip chart or let your computer help you out onscreen.

2. Don’t choose the wrong type of visuals for the size of audience you’ll have.
Flip charts work with 15 or fewer people, but they’re useless with groups of any size. (You can accommodate slightly larger groups by elevating the chart and writing huge with dark markers.) Showing a video on a TV monitor is effective for a small group, but you’ll need several monitors for a medium-sized group. Overhead transparencies work best for medium to large groups.

3. Unless you’re Oprah, don’t supply handouts during your presentation.
Top presenters agree that you’ve got to be really, really good to compete with your handouts for your audience’s attention. So unless they need the information in the handout to understand your presentation, distribute the materials after you’ve finished speaking.

4. Don’t blind your audience with overly complex, colorful graphics.
Each visual should communicate a single idea. Far too many speakers create complex, wildly colorful graphics on their computers and then use them in their presentations, even when those nifty graphics have little or nothing to do with the message. Don’t allow “graphic overkill” to confuse the points you’re trying to make.

5. Don’t intersperse visuals throughout your presentation; group them, instead.
Arrange your speech so that any visuals are shown in an unbroken sequence, concept by concept. It’s too distracting to the audience if you keep turning the lights up and down, while you show visuals intermittently as you talk.

6. Don’t show a visual presentation that’s longer than 25 minutes.
Whether you’ve got a computer-generated presentation, a video or slide show, you’re likely to lose your audience after 20 to 25 minutes. Also, be sure to “de-brief” the audience afterward, explaining how the video relates to your subject matter or message.

7. Don’t expect your audience to read tiny handwriting or too-small type.
If you’re writing on a flip chart or adding information to an overhead, print in BIG letters. Don’t cram too much information on one page or one overhead. Red and green lettering are difficult to read, so avoid those colors in markers or typefaces. Onscreen typefaces should be in at least 30-point type.

8. Don’t try to run the lights while giving your presentation.
Ask someone beforehand to be responsible for dimming and raising the lights for you so you won’t have to interrupt your presentation — and leave your audience hanging — while you sprint to the back of the room to turn the lights off or on.

9. Don’t use overheads or graphics that haven’t been carefully proofread by someone else.
Spelling errors in 36-point type, shown on screen to 200 of your coworkers at an important company meeting, will not enhance your professional image. Always have others you know to be excellent proofreaders inspect your overheads, handouts and computer-generated presentations.

10. Don’t EVER make a presentation without thoroughly checking out the equipment beforehand.
Nothing is more exasperating for an audience than to have to sit through a presentation where the speaker fumbles around with malfunctioning equipment. Arrive plenty early to check out the equipment set up, and be sure to have Plan B firmly in mind. What will you do if the computer crashes? If the bulb burns out in the overhead projector? If the screen you ordered doesn’t arrive? Contingency planning is the key to success when using equipment — and a couple of spare extension cords won’t hurt, either!