Add a form or link to each page of your website and to posts on your blog.
In your regular emails, add a link in your signature line to invite recipients to join your email marketing list. When you send something to your list, include both a “forward me” and a “sign up” feature in your e-newsletters, announcements and other messages.
Place your sign-up form on your Facebook page, or use a prominent link to a hosted web form. Do the same with a link in your Twitter profile. If you participate in other social media such as Pinterest or LinkedIn, do some Google searches to explore how to leverage your presence there for building your email list.
Setup a tablet to use at shows to allow new subscribers to join quickly. You can build, or sometimes rent stands from the show, that allow you to secure your tablet and keep it at a height to make joining your list easy.