The first step was to make the ‘add to cart’ indicator apparent via a popup or menu navigation slide-down.

After this, as a general rule, it’s important to not have the notification auto-hide after a certain amount of time. This can create frustration if the customer is reading the contents, about to click on it, and it just disappears.

Users are getting accustomed to the action of clicking off a popup to exit, use this inclination by only closing out the mini-cart when a user clicks elsewhere.