Nonverbal communication such as facial expressions, gestures, posture, and proxemics account for over half of messages sent. First impressions are formed based on a person's appearance, enthusiasm, and tone of voice. Nonverbal cues should reinforce verbal messages to ensure effective communication, while inconsistent cues can cancel each other out. Factors like dress, eye contact, handshake, and body language impact first impressions and the ability to develop trust and rapport.