4. Smart company
You can judge a person based on the company they keep. By that we mean that you can understand what kind of person somebody is based on the people them hang out with, interact with all the time and so on. If you are a smart person then you will notice that you hang around with other smart and creative people. This is because you relish in the competitive nature of your conversations and the high standards you all can maintain. If you are always surrounded by dumb people then it may be time to change your companions.