Anybody who fills in the form to join your list wants you to provide them with information. They are willing to buy from you if the information you provide demonstrates that you can be trusted and are the expert that you claim to be.
You can further reinforced your credibility by sending your subscribers the link of your latest articles that are published on public ezine sites or directories. Most people will perceive authors of ezine sites as credible and experts in their industry.
Never ever try to short sell yourself by getting too early in the selling act before you even establish yourself. What you should do is to wait for your autoresponder series to hit 7 before attempting to start selling your products or services.