Well, my first question would be if you are a degreed Interior Designer? Do they only want local firms, trade only? there may be more to this than having done your own home or the home of a friend although it sounds as if you may have a degree or related experience in a related field (set design) Below is taken from SF deco showcase California site
http://www.sfuhs.org/showcase/pages/press.html 'The San Francisco Decorator Showcase is a nationally recognized as one of the premier showcase houses in the country. More than 25 years of excellence in design and the decorative arts. Nearly 30 spaces furnished and presented to the public by leading landscape and interior designers. Featured year-round on Home & Garden Television and in national magazines.' You may not be able to do this in your area because of lack of accredidation Interior designers normally need a college education, in part because very few clients -– especially commercial ones –- are willing to trust designers without formal credentials to create their living and working spaces. This includes insurance issues and certain building code knowledge. Interior design IS subject to government regulations. Twenty-one states and the District of Columbia require interior designers to be licensed. Because licensing is not mandatory in all states, an interior designer's professional standing is important. Many designers join trade organizations like the American Society of Interior Designers ASID, IIDA, CBIA and FIDER. Membership in such associations usually requires the completion of three or four years of post-secondary education in design, at least two years of practical experience in the field and a passing grade on the National Council for Interior Design qualification examination. Which is as grueling as getting your Bar exam done.