It is very important to offer something visual in your presentation, to make it clearer for your audience, but even more, to make it more memorable (check the post on Memory hooks).
Don’t let the visuals distract the attention of your audience. You must still be in the centre of their attention, not your visuals!
For an example of effective usage of visuals, check out some of RSA Animate videos.
Powerpoint is an amazingly powerful tool, which can significantly improve your presentation. Yet did you ever hear of the term “death by powerpoint”? Be careful not to exhaust your audience with too many slides, and not to offer more information than one can process. Keep it simple, innovative, inspiring, memorable, and always be sure that your powerpoint supports your message, and you as a speaker, in the best possible way.
Here you can find some advices on how to use powerpoint efficiently: http://www.thinkoutsidetheslide.com/
If you would like to see how to use slides to hook your audience in a fascinating way, check Hans Rosling in his TED talks:
Flipcharts are great for presentations in which you would like to keep the audience more involved, and things more flexible.
Amazing book on how to create some wonderful flipcharts is called “The Big Book of Flip Charts” by Robert W. Lucas.
Some inspiring and practical advices can be found in this great blog:
You can use picture in the presentation to create Memory hooks for the ideas that you are conveying, and you can use them to inspire, create atmosphere, evoke the emotion, to make people smile, or to touch their hearts. Pictures are one of the most powerful tools, and it is definitely worth putting some effort into finding the right pictures for your presentation.
You are your own visual
Your own appearance is visual of its own. No matter how unfair it sounds, it is a fact that some people appear more credible, more expert, or more lost then others. Luckily, big part of the impression that you might leave is in your own power. Use your posture, clothes and accessories in a way that you leave a good impression, but also to support your presentation in a way that you grab the attention of your audience instead of potentially distracting them.
Good video about visual thinking (with some original slides as well) can be found here:
TEDx Talk from Sunni Brown about Creating the doodle revolution.