Research individual personality traits.
What does a Personality Psychologist do?
Personality psychology is the field dedicated to observing and researching human behavior. A Personality Psychologist looks at the way people interact, and tries to understand why people act and feel the way they do. A Personality Psychologist is like an Animal Behaviorist in that he or she focuses on one aspect, be it emotion or action. But of course, instead of animals, people are the subject for Personality Psychologists.
This is a title that covers a lot of different jobs. You can teach at a university, consult for a sales company, work as a hiring expert for a human resources department, or train Police Officers on how to respond during tense situations. Pretty much any government office or corporation that needs insight into other people hires for this position.
Where you work will determine your day-to-day responsibilities. For example, as a Teacher, you spend time with students in a classroom, while as a Consultant for a sales company, you will never grade a dozen undergrad papers.
Wherever you work though, your job is to apply your understanding and research to the way people behave and interact. You can tackle specific experiments, especially if you work in a research facility or school, and apply quantitative research methods to psychological issues. For example, you might prove that when people face a certain decision, X number always choose option A.
In other words, you work to prove facts about human nature. And you do this by observing people alone and in groups to get a feel for how and why they work the way they do.