When it comes to a successful word-of-mouth advertising campaign, one of the key ingredients is expertise. If you are not viewed as an expert in what you do, nobody will trust to recommend you to their friends and family. I spent some time talking about expertise as well as 4 other ingredients in a previous post titled 5 warning signs that your word-of-mouth strategy will never go viral.
The main thing we believe at Nichevertising is that the #1 goal for a bootstrapping entrepreneur must be to create a viral referral loop. We define a viral referral loop as the ability to get your best customers to provide at least 3 referrals every month/quarter/year (whatever fits your business), and then get at least 50% of those referrals to do the same. I blogged about it not long ago in a post titled Why creating a viral loop is the only goal that matters.