Your clothes communicate identity, personality, and image. Attire is the first thing your audience will see during your presentation, and they'll be more open to your message if you carry yourself with confidence. And you’ll likely feel more certain of yourself if you’re dressed in professional yet comfortable clothing.
Keep this rule in mind: dress slightly more formally than you anticipate your audience will dress. Be sure you plan your outfit ahead of time so you're not panicking at the last minute, looking for a clean shirt.
Layers are a good choice, so you can adjust your clothes to the room temperature. Layers have another advantage as well: if you find you're dressed too formally for the event, removing a jacket is an easy way to make your appearance more casual.
Try your outfit on ahead of time to be sure it fits well and allows you to move comfortably. Avoid anything too tight or too revealing. Remember: you want people focusing on the body of your argument, rather than your actual body!
The most important principle is to match your appearance to the occasion and the audience. If you’re giving a presentation to a class, dressing up a bit more than you do every day is probably fine. However, if you're presenting to an audience of professionals, you should dress up with a jacket, suit, or office wear. Don’t dress as if you’re headed to a wedding or a nightclub. Think professional, rather than festive.
Since you want to draw attention to your ideas rather than your appearance, it's usually best to wear something understated. Avoid flashy or distracting accessories like ties with cartoon characters or jangling bracelets. And don't forget the little details: polish your shoes, iron your shirt, and comb your hair!
Some examples of appropriate dress for a presentation: