Dare not make sales calls in front of colleagues, how to overcome this psychology?

This is a sign of lack of confidence. As long as you are worried that you have not introduced the product to your customers well, this is normal. Since you are familiar with the product, you can write an introduction first, practice at home, pay attention to your tone, address and words, and listen to how the customer service staff answers the phone. In fact, you don't have to worry about others, and others won't care too much about you.