We rebuild your highest leverage page and run it as a live split test against the page you have now. Revenue per visitor is the scoreboard.
Usually the product page, because that is where the money is decided. One page, rebuilt properly, rather than a list of opinions about the whole store.
Your traffic split between the new page and your current one. Up to five iterations. The result decides, not the loudest view in the room.
Two or three tests a month against a live control, measured in revenue per visitor so a change in average order value cannot flatter the number.
Product page rebuilds and ongoing split testing for ecommerce brands, with every figure measured on the brand's own traffic.