Regularly analyzing your best selling products is a good idea.
You can go one step beyond that by analyzing how your products lead to customers, specifically high lifetime value customers (LTV). These customers are likely to be some of your best customers so by knowing what they purchase you can prioritize your merchandising around them.
To do this take each product and find which customers ordered it at specific times (e.g. 1st order, 2nd order, etc). Then find out what those customer's LTV is and rank your products based on the Total LTV.
You'll end up with something like this:
(This is taken from the Nth Product Analysis in the Repeat Customer Insights demo)
Looking at this sample, the Thick Wool Gloves are a key product with both the Average LTV and Total LTV higher than any other product.
This means customers who buy the Thick Wool Gloves in their first order are coming back and spending more money in their return purchases. Those should be promoted heavily and new merchandise developed similar to them (e.g. thin wool gloves, 3-packs, etc)
Best-selling products are still great but add in an analysis like this to find the best-customer producing products.
If you this analysis done for you, it's included in Repeat Customer Insights. It also includes a version that go into variants so you can see which variants are best.
Promote products that create your best customers
When it's time to run a promotion, how do you pick the products to feature? Best sellers are okay but wouldn't it better to promote the products that crate the best customers? Repeat Customer Insights will analyze your product and buyer behavior to show which products and variants lead to the highest quality customers.