You can do this as well. If you have a stall at mailing list a trade show have a free prize draw and gather your Opt-in members from the business cards obtained. The above three ideas should give you a good start to build your e-mail list and this will then give you the bedrock for your ongoing e-mail marketing campaigns.
As with any campaign you should track your success in all these areas.Which marketing track gives you the greatest number of quality mailing list Opt-in email addresses. Which campaigns deliver the best revenue returns? You must track this so that you can amend your future opt-in campaigns to take more advantage of the winning themes.
You also need to understand which marketing campaigns to your e-mail list deliver the best returns and focus on them in the future. As mailing list with all new methods of working the only way to know what works is to get out there and market. That is the only way you will learn what works and what does not work and amend your future strategies accordingly.