So many people talk about quick growth and numbers that it can be really discouraging AND have you chasing crazy numbers. Because email subscribers tend to be more high quality, that also means the list building tends to be slower over time. So first of all–ignore all the big talk about quick growth and high numbers. If you are trying to grow true, raving fans in your list, then your growth may have spikes, but should continue over time. Don’t ever stop thinking about email! Continue to consider what you can offer, where on your blog you can optimize for signups, and change things every few months.
Include social sharing buttons and an "Email to a Friend" button in your marketing emails. That way, you'll gain access to their friends, colleagues, and networks and expand your contact list. At the bottom of your emails, include a "Subscribe" CTA as a simple text-based link so that the people receiving the forwarded emails can easily opt-in, too.
But your money could also be spent on advertising your product to a community – not a random set of people For example, John Lee Dumas runs a podcast called Entrepreneur on Fire. If you have a great product that will make an entrepreneur’s life easy, you can hit him up there. His episodes cover all things entrepreneurial and he boasts a loyal audience. His September listens totaled more than 1 million. John even recently published a useful blog post about podcast sponsorships.