Discount policy; discount for new users
For customers who are in your store for the first time, you can display a pop-up that gives them the choice to subscribe to the newsletter now or not to take advantage of the promotion. There can also be a discount for the first purchase. In this way you can boost the loyalty of new users but also encourage them to make a purchase.
If users skip this pop-up for the first time, you can display a pop-up on the second time, after adding a product to the shopping cart or as an exit pop-up if they decide to leave your page.