The focus of email marketing list building should be on providing utility, value or entertainment to your subscribers. As a business, you’ll need to figure out how your current business and content can provide and deliver value to your target audience in order to get their permission to establish an “email relationship” with them. If you don’t have one yet, you’ll want to make sure you’ve put thought and invested in establishing a strong content marketing strategy and creative process.
At a tactical level, this might look like “Sign up to get updates when we publish new blog posts”. Or, you might invite site visitors to “sign up to get our free eBook on xyz topic”.
More advanced approaches might include gathering and curating valuable content you have (seminars, technical documentations, expert employees, etc). You could also consider if your target audience would find value in an automated education series (almost like a light course) leveraging expertise and knowledge your have within the business. Invite target audience or website visitors to sign up to “get our 12 part series on xyz topic” via email.
Regardless, the content should be on-brand and aligned to what your business does so it builds up your business and makes a case for your products or services.
One final key thought: think of your email as a “Product” in order to execute on an effective list building strategy. Having that, you follow the usual marketing process and leverage any number of advertising tactics (SEO, paid media, etc) to drive traffic into the funnel and build up your list.
And don’t forget about the importance of email list hygiene and ongoing list engagement for inbox delivery success.