In order to help you type people quickly here's some signs to look for. They are shown as a positive correlation, the opposite is a tendency to the other mode.

Extroverts like things occuring around them. Active Engagement.
Introverts like ideas and therefore less activeness around themselves. Disengagement from people/process.

These are the signs introversion

Not really interested in a fast paced job.
Not interested in a wide circle of acquaintances.
You don't spend your leisure time actively socializing with a group of people, attending social gatherings.
You tend to be somewhat reserved and distant in communication.
You find it difficult to speak out and attract attention.
You don't try to get engaged in workplace social life
You prefer quiet and relaxed surroundings
You prefer to talk to a small number of people rather than a large number.
You enjoy solitary activities.


Signs of extroversion

The opposite to the above!