Selling

"Add $12.50 more for free shipping" with a progress bar in the mini-cart, the cart and the checkout summary.

"Often bought together" on the product page, from the orders: picks with checkboxes, a total and one Add to Cart.

A delivery date and time window picked in checkout, kept on the order and shown everywhere the order is.

SKUs and quantities, a pasted list or a CSV file, straight into the cart.

In-Store Pickup in Zero Checkout and a store locator page with maps.