Have you ever heard advice to the tune of "If you don't know, then fake it?" That advice only gets you so far. In today's fast paced, over advertised environment, being honest will get you a lot farther than faking it. People are looking for things that are authentic and genuine... not looking for someone to tell them what they want to hear.
When promoting your work, rely on your true areas of expertise and present your strengths to your audience. You're much more likely to get a good response to your message.