Step 3: Product page, cart, and checkout — in that order
On the product page, check whether the product, its benefits, its price logic, and its proof are clear at the moment of decision, and whether the buy box stays in reach on a phone. On the homepage, check navigation, hierarchy, and whether a new visitor understands what you sell within seconds. On collection pages, check whether shoppers can find, filter, and compare the right products.
In the cart, check the full path from add to cart to checkout: shipping costs shown early, quantity changes that work, trust badges visible, and one obvious path forward. In checkout, check surprise costs, too many fields, missing guest checkout, unclear delivery promises, and error messages that do not help. A Shopify checkout audit is the fastest way to protect ad spend, because checkout is where the highest-intent buyers drop off.
Work in that order on purpose. A product page with high exits needs a different solution than a checkout with high abandonment, and a checkout project is often the wrong first call when the product page is where the money actually leaks.