Imagine that you're preparing for an important meeting. Everything seems perfect: Your hair looks great; your new suit fits well; your shoes are polished. You've done everything possible to make a great first impression.

But some things are beyond our control. Everyone we meet will make assumptions about us...and we will do the same. How quickly do people make decisions about others?

33% of managers know within 90 seconds if they will hire you

People will determine if you're trustworthy within 1/10 of a second

Before the brain registers your gender, it has already decided if you are likable

"There can be as much value in the blink of an eye as in months of rational analysis." wrote Malcolm Gladwell, in his best-seller Blink: The Power of Thinking Without Thinking. Gladwell introduced the concept of "thin slicing," the lightening-quick process of deciding characteristics, from attractiveness to intelligence to financial success.

Knowing about thin slicing can help you influence what people decide within seconds of meeting you, and how to make a great first impression. Here are four things that people judge instantly--and how to make them work to your advantage:

If you respect yourself. Pay attention to how you dress for any type of encounter. Remember that nonverbal cues account for 55% of all communication. Wearing ill-fitting, wrinkled, or inappropriate clothing sends the message that you don't care how you look...and that you probably have a messy work ethic, too. Don't neglect grooming, either. Clean nails and neat hair indicate pride in appearance. If you have status. Power and status are perceived by how you dress and how you move. Business Insider reported the results of a Canadian study, showing well-dressed people were expected to and be promoted more often. Stand up straight, with your shoulders back, to indicate confidence and success. Develop a firm handshake to establish instant rapport. If you're intelligent. A study done by Nora A. Murphy, PhD, at Loyola Marymount University found that eye contact is a key factor in how your intelligence is perceived. "Looking while speaking was a key behavior," she wrote. "It significantly correlated with IQ, was successfully manipulated by impression-managing targets, and contributed to higher perceived intelligence ratings." Another tip: Raise your eyebrows! By opening your eyes slightly more than normal, you'll create the "eyebrow flash" that is the universal signal of recognition and acceptance. If you'll be liked. Your attitude is everything; people will read it immediately. A genuine smile says, "I'm friendly and non-threatening." Offer a smile with your handshake, and use eye contact to show interest and openness. (Notice each person's eye color to improve your eye contact.) When sitting, lean in slightly to indicate curiosity and engagement.

How much you know about the ways that others make decisions about you in only a few milliseconds can be useful. With good information, you can ensure that you're able to present yourself in a positive manner.