If you consider yourself to be a smart and successful individual, you should always watch your body language. Here is what you must not do.

1. Having a sad expression delivers the message that you are unhappy by people surrounding you. This is how others may interpret your body language. Avoid it if you do not want to disappoint people around you. Smiling is the only way to deal with people, especially those you are not very close with. Strangers who do not yet know you want to see the best traits of your character and your friendly nature. 

2. It’s sometimes very difficult or even impossible to control your facial expression. Even if you are good at controlling your words and what you say, then your eyes, smile and hands can tell the other person what’s going on in your head. Make sure that your words do not contradict your facial expression. Relax and do not feel nervous since it will only worsen the situation. A friendly smile is very powerful. Slow down if you feel you are at a loss.