Design a referral form and include it in your outgoing mail, with your newsletter, and e-zine and post it on your website.

Since people are often unsure whether their contacts will find your product or service useful or relevant help them by asking questions that relate to the benefits your product or service provide (for example, “Who do you know who would benefit from…..?” or “Who do you know who needs help with [the problem that your product or service is resolving]?”