By now you should be able to recognize emotions in others and even your own emotions better. You should have a better understanding of what these emotions mean and what are some causes for these emotions.
Now whenever you are walking down the street if you see someones face try to think of what they are feeling. If they look sad maybe give them a smile. If they are happy be happy with them. Emotions are a wonderful way to communicate without speaking. However, remember some people may not be so easy to figure out and you do not want to hurt anyones feelings by saying that they act as though they are "mad" when maybe they are not.