People can tell a lot about you based on the way you hold your body and inadvertant gestures you make. Non-verbal cues give people a glimpse into our inner world. When we display confidence in our body postures people are more likely to do business with us. It is a basic cue connected to our biological nature that many people are not aware of. With a little practice you can improve.
Little gestures, body movements, and facial expressions can tell a lot about us. For example, covering the mouth may mean your hiding something, tapping of fingers could mean anxious, staring could mean a challenge or commitment. We may not be overtly or consciously aware of the displays we are giving but that doesn't mean they don't exist.
Our subconscious gives off these signals to help insure we are connected to our social environment while giving off hints to our inner experiences. It is what makes us social creatures and has helped us survive as a species.
When we were in small groups and know each other well we were much better at interpreting each others signals better. Our subconscious may accurately pick up on a signal but it could be out of context or could have a different meaning unrelated to the person they are facing.
This is one reason why it takes time to know one another and create an attachment. The more we interpret and understand each others signals, can recollect them in a conscious way, the more we trust each other. Strangers don't have this luxury and so business success is often based on how we appear to others.
However, in a bigger world where people don't know each other, may not have empathy, or consider any social obligations it is important to show confidence. This gives the signal that you are capable, confident, and a stand up kind of person. It tells people who are dishonest in their intentions to keep walking.
During your course of business interactions with others make sure you display confidence to create greater trust that leads to higher sales and deals. Avoid being arrogant as this can send an opposite signal. When you give off confidence you will find people will gravitate toward you, give you preference in dealings, and think highly of you.