Eye contact is one of the most evident methods of nonverbal communication. It has been said that the eyes are the window to the soul. Most people, when they are talking to you, will watch your eyes to see if you are looking away as you are supposedly listening. When someone speaks to another person and that person is looking away as they are listening it says loud and clear "I am distracted." Equally important is that when you speak to others, you look directly into their eyes, rather than looking around the room as you speak.
Our body language reflects how we feel about what we are hearing or saying or even just thinking. If we are slumped over it says we are "depressed." If we stand or sit straight it says we have confidence. The elbow dig into someone's side says "I am kidding and comfortable enough with this person to jest." Crossing our arms in front of our body says "I am in charge here." Keeping your arms to your side and standing up straight says "I am open-minded about this particular situation."
Paralinguistics, meaning tone, pitch, loudness, inflection and rhythm of your voice is considered one of the nonverbal communication types. Even though this includes "sound" of our voice, how we say what we say represents things such as sarcasm, anger, intimacy or even being whiny. The expression "That's great" is a common one that by using a different tone, the meaning changes drastically.
In addition to eye contact, our facial expressions tell a lot about how we feel about what we are hearing or saying. A raised eyebrow can change what you say from being sincere to being devious. The actor Jack Nicholson is famous for his raised eyebrow expressions. Smiling as you listen says, "I agree." A slight frown and lowered eyebrows says, "I don't quite understand." Closing your eyes and smirking says, "I don't believe you." Reading a person's face as they speak can help you to better understand how they feel about what they are saying.