If you run a business that can offer case studies or data, you will get the best results by sharing these things with your list members.
For example, if you are an expert at selling items on JVZoo, you can show real-life case studies from your sales last week. Show people how you write your copy, price your items, and get the most out of each sale.
This works across many different types of businesses. The point is that people like to see real-time results, and they are often impressed by and respond to them.
This works very well if you are eventually going to promote a product that you have used. So, as a JVZoo seller, you might have taken some courses, say on Udemy, that helped you create information products.
You can recommend the same courses to other people and earn commission from them if you don't have your own product (or to supplement your product offerings to your subscribers).