It is cheaper to market to customers you already have than to find new customers. Can you create a new product or service that your current customers need?
This is part of the reason it is so important to build a customer list. Start collecting emails and contact information from your customers. Offer them a newsletter with information that they want.
Remember it is about them and if you add value to their life then you will have a customer for life who will be interested in more and more of your services.
A good way to keep track of your customers is with a CRM (customer relationship management). In a CRM you can track when and how you last contacted your customer, what is of interest to them and when you want to contact them again. [LINK=https://payments.zoho.com/ResellerCustomerSignUp.do?id=523c937bbbb0f5db9b29cfaedd74647d27c5ff4613d245cd1d5ec2e6bc30085a]Zoho CRM[/LINK] is a great CRM that is free for up to 10 users and affordably priced after that.