I learned last week that a few email marketing systems will automatically unsubscribe your customers if they place an order in Shopify and don't check the Accept Marketing checkbox in checkout.
It's commonly listed in checkout as "Keep me up to date on news and offers" or "Email me with news and offers" but each and every theme can use something different.
Depending on your theme, the copywriting might be far off for your brand and causing customers to not be incentivized to enable it. Which means they aren't getting into your marketing systems and they aren't getting any new customer campaigns you've setup.
The solution is to edit the text your theme uses for this to make it clearer and more relevant for your brand (e.g. "Sign-up for free fashion tips for the lumberjack in your family"). Shopify allows every store to edit the wording using their editor.
This simple change could help you keep more customers around and ordering again. Use the Repeat Purchase Rate in Repeat Customer Insights to measure the impact of this.
Learn which products build the best customers
Find which products create the most valuable customers with the First Product Analysis in Repeat Customer Insights. It goes beyond your best sellers by looking at long-term purchasing and retention behavior of your customers.