If you wear a cloth sack to an interview with a prospective client, you probably are not going to get the gig (unless the gig is in avant-garde couture—then you are a lock). Building credibility fast is crucial with prospects, and in a post at Consultant Journal, Andréa Coutu provides a few pointers toward that end.
There are many ways to build credibility in a broad sense with prospects. For instance, maintaining a blog, writing for industry publications, holding speaking engagements, and keeping up with sharing ideas on social media are all effective ways to build a personal brand—and in turn generate credibility. But ultimately, the best way to have credibility is to build a track record of sterling results and reliability.
For elaboration on these ideas, you can view the full post here: http://consultantjournal.com/blog/building-credibility-with-potential-clients