Successful selling requires more than a desire to make money. It results from a combination of product knowledge, professional expertise and personal confidence, all of which are developed through perpetual learning. What are you doing every day to improve your skill levels in selling, communicating, building relationships and networking? How much do you know about your product?
Don't forget that you're a product, too. It's you that customers are actually buying. You can improve that product by finding mentors, observing what successful people do and applying some of their methods to your own creative style. (After all, you are what's most unique about what you sell.)
Your knowledge and commitment to learning will produce enough enthusiasm to sell with passion. The more you learn, the clearer your picture of what it takes to succeed and the more excited you get about taking the necessary actions.