Presentation skills that involve public speaking are an asset that many recognize to be important for their careers or during their study. One way to learn how to maintain eye contact and address clearly as a speaker is to use virtual audiences (VA) that simulate the reactions of a live public. A mixed-methods exploratory study has been conducted to conceptualize the design of such a VA. The purpose was to research how the nonverbal cues of live audiences vary depending on a speaker's gaze patterns (gazing towards the audience vs. gazing towards the presentation slides or notes) and vocal loudness (low vs. normal). 36 students (listeners) were videotaped during a public speaking situation. The analysis shows that the speaker's gaze patterns and vocal loudness influenced several nonverbal cues the audience displayed. The results could be implemented in the design of VAs by making them responsive in real time to variations in gazing patterns and voice loudness of the speakers (trainees).