The Johari Window Model was invented by two American psychologists Luft and Ingham, and is also known as the "disclosure or feedback model of self awareness." Basically, it is a tool to look at a social situation and have successful communication.
Learn the basics. What is the Johari window? The Johari window represents how much people choose to reveal themselves. Shy or introverted people do not readily share their feelings, so they have more of a closed window. Open or extroverted people are willing to talk to anyone on any subject, so their window is wide open.
Use people's window to your advantage. To get a message across, take a moment to notice the audience. Shy people are more comfortable around a quiet, less invasive personality. These people tend to have jobs that require more analytical thinking, like accounting. Open people are more comfortable around a bold personality and have interpersonal jobs like marketing. When speaking to each group of people, adjust your Johari window to theirs. As they begin to feel a "connection" with you, your message becomes more persuasive.
Adjust your window accordingly. A open window requires joking around, having fun, being more candid. A closed window still involves speaking, but with less of an excited voice and more of a straight to the point style.
Notice cues. People provide clues to their window and these can be very subtle. Crossing the arms, making no eye contact, and leaning away from the speaker indicate a closed Johari window. Smiling first, initiating slight intimate contacts, and having a gabby voice indicate an open Johari window. Try to mirror your body language and speaking style accordingly. You might find that slowly even people with closed windows begin to open up.