Hello Mike
When you say developer, do you mean web developer?
The best marketing is anticipated, relevant and timely. (That is why Adwords is so successful: users expect the adverts on the side of their search results, the adverts are relevant to what they are searching for and they are certainly timely as they're shown while the user is looking for something.)
Not all marketing can be anticipated but that doesn't mean it can't be relevant and timely. Assuming you are a web developer, you could try
contacting local start-ups. A UK start-up or a new business that's only been trading a few months is an ideal lead in terms of relevancy and timing: they are unlikely to have a site and will be looking to increase awareness of their business.