My answer to Is it a good idea to offer to work for free in order to prove my potential?
Answer by Ken Larson:
Be prepared to provide information, samples and valuable service gratis as a marketing tool. Introduce yourself and then immediately engage the client with your presentation tools available to bring your expertise to whatever topic they are interested in.
Let them take you where they want to go with their concerns and their needs. Apply your presentation tools and expertise dynamically on the fly in a sincere manner to those concerns and needs and you will be in demand for follow up business.