1. Gestures can make you look more natural as a speaker. In everyday conversation, most people talk with their hands to some extent. Using gestures in a presentation helps your audience see you as someone who is simply having a conversation with them.
2. Research shows that adding gestures helps your audience understand the information you are sharing—even if you are using general, non-specific hand movements. This connection becomes especially important if the information that you are presentation is complicated.
3. To optimize the efficacy of your gestures, adjust their size to the size of your audience (see video for details). For example, if you are talking to a few people, move your hands/arms from your wrists. If your audience is a few dozen people, move your arms from your elbows. If your audience is a hundred people or larger, move your arms from your shoulders. This ensures that your gestures feel appropriate to the people watching your presentation.
4. One of the primary concerns I hear from students and clients who are anxious about presenting is what to do with their hands when they are presenting. If you become comfortable using gestures as you present, you have alleviated any concern over what to do with your hands. You do not need to count off points with your fingers or anything nearly that complicated. Simply moving your hands in a general manner is enough to help engage your audience and make you appear more comfortable and confident as a presenter. I bet it will make you feel more confident, too!