The best way to find new customers- especially on the internet, is to give stuff away. You are proving that you have your customer's best intererst at heart and allow them to see what you are about risk free.
This works great if you are giving away information or advice. If you are giving product away be sure to narrow your gifts to your target market or you'll go broke. There are ways to give away part of your product for free- free consultation, free book chapter, free shampoo with haircut...
Humans are naturally reciprocal and will try to give you something back. The ones that don't are the creeps you don't want as customers anyway.
Give people a reason to start the relationship and make sure you are good enough to keep them.
What could you give people to facilitate them giving you back a chance at their business?