One of the most important assets for a salesperson is confidence. It's remarkable how a positive mindset is such a successful sales driver. Science even says so.
A researcher for CNN, suggests that "Happiness raises nearly every business and educational outcome: raising sales by 37%, productivity by 31%, and accuracy on tasks by 19%, as well as a myriad of health and quality-of-life improvements."
Customers and clients recognize and know if you are happy. So do your best to be positive. I recognize that this can be difficult at times, so here are some tips from the same article listed above:
Believe in yourself and be happy. Sales professionals know that you're far more likely to achieve success when you approach your job with confidence.