A long checkout form looks intimidating at the first glance. But if you break it into multiple steps, you can collect the basic details first followed by billing and shipping. The advantage of this approach is that people keep moving forward one step at a time. It’s like a slippery slope.
Use product & quantity selector to give the control to users
You can append a mini cart on the checkout page. Let users delete and recover deleted items. Give them the option to adjust the quantity of the item(s) they’re buying. It’s not just great for your conversions but also your order value!

Demo : https://www.gplmonster.com/downloads/woofunnels-optimize-woocommerce-checkout-with-aero/