Browse through websites and try to identify issues with design/marketing/or whatever you do, then get in touch with the owners and try to help them solve the is

Browse through websites and try to identify issues with design/marketing/or whatever you do, then get in touch with the owners and try to help them solve the issues. You'll know instantly (judging by the response) whether there is potential for you to work together. Nothing endears you to the potential clients more than free advice. This method has got a low success rate, so you'll need to go through a number of websites before you hit a positive response. And it's important to make sure you've got a "presence" (like ekpyrotic and tagabek said) It may make things easier if you target websites that are based in your area (or within a driving distance).