One secret (not so secret) method to get repeat customers is to force them.
I mean let your customers opt-in for receiving regular shipments of your fine products.
Jokes aside, creating subscription or recurring orders can be a solid strategy to ensure repeat orders.
The product type will need to make sense: replenishment products or the mystery-box subscriptions seem to work well.
You could start by taking your most popular two products that fit together and creating a subscription version of them. Even with a slight subscriber discount, this could be a profitable product line after the first few renewals.
Once you develop one that starts to sell, then you can start to experiment on a second offer and try to improve.
If you haven't installed Repeat Customer Insights yet, it's an easy way to get a detailed look at your customer behavior. With the Customer Purchase Latency report you can find the intervals customers are reordering at and tailor your subscriptions around them.