Pick your template wisely
Let's face it, every day we mock at least one person's outfit or ability to match colors. Heck, Joan Rivers has made a career of it (somehow). There are few among us who can design well.
When you're making a new presentation, find professional designers, and ask them to create your templates. Don't try to make them yourself.
Bad use of colors or fonts can make the presentation unreadable and can distract terribly. If you can't find a good designer, use a basic, pre-made template with very few flourishes. It's better to use a bare template, than an eye-jarring one.