Always have a smile and speak clearly.

Always have a smile and speak clearly. 

Most importantly, look them right in the eye. 

This will make the other person feel as if you're really paying attention to them.

If you don't know the person's name, say, "nice to meet you" or, "nice to see you again.”

If you are greeting an adult, smile politely and say hello.

Or, you can ask them politely, by saying, "It is good to see you again; unfortunately, I have forgotten your name."

 It may seem a touch impolite, but it is a lot better than saying the wrong name.