Effective email marketing involves sending out to a base of users who have given their consent to receive emails. They must be interested in your product, service, or online store. Only then will the newsletter be interesting and the transformation of potential buyers into real ones will happen organically. Trust marketing involves a personal aspect and information relevant to the client. Study your audience, give them more valuable information than you promised. The easiest way to find out how much people need your content is to ask them to leave a comment or take a quick test with a selection of topics that are relevant to them.