Even simple mistakes can cause your audience to question your credibility. Show your enthusiasm for your product and business, and that enthusiasm will be contagious. Your audience will be more likely to believe in your product if you show that YOU believe in it. One way you can do this is to explain why you personally decided to start your business and why you personally believe people should become clients or customers. Create goodwill with the audience.
People are more likely to trust a person who seems to be acting in their benefit.
Let the audience know that you are willing to go that extra mile to please them. A personal sense of commitment to the customer can be as effective as any advertisement. Your communication with your customers can be a great help here. For instance, personalized, interested emails will do a lot more to make your customers feel comfortable than any number of form-letter emails will. Show your associations.