When developing your website, consistently use fonts and colors throughout your website. Too many colors and fonts across too many pages can confuse people, and they may even think that they are no longer on your website. You don't want to confuse your visitors. To achieve the maximum cohesiveness, also use the same font and color scheme in any brochure or literature you send out for your company.
If you are going to permit a company that deals in website design and development work on your website, make sure to study their portfolio. Ensure they've had clients with good reputations, and double check that the clients really were satisfied with their work. A web designer's portfolio will let you know if their style is right for your site and if they produce quality web pages.