In 2014 I worked with Kaspersky sales department on improving our shopping carts for several Europe countries (kaspersky.fr). The goal was to raise conversion rate using existing data, Google Analytics and past A/B test results.
French version was our basis that's why all mockups below are in French.
Bear in mind that this is not a final graphic design.
All our regional shopping carts were developed long ago by different people so we had to bring visual style to unique standards and make UX the same for every country, maintaining minimalistic graphic design to help people to focus on buying process and not visual effects.
There is no need to compare items in the shopping cart and taking into account that people usually buy only one or two items (Google Analytics), I set aside table layout in favour of a card view.
We were moving step by step improving separate areas. I redesigned license selection and promo code activation to make these functions as simple as possible and self explanatory.
I added a new section with order summary as we knew due to previous tests that people miss it a lot.
All forms were examined and fixed, because even the smallest problems reduced conversion rate. Number of required fields was minimized, layout bugs and error messages were fixed, also entry fields masks were added.
Delivery form state when shipping address differs from the customer's address:
Last but not least payment step was fixed too — we added an informational block with order details, readjusted an input form to get rid of layout bugs and to fix every small problem to boost conversion.
When these mockups were finished graphical designers got into the game to complete visual style. Then we A/B tested new shopping cart to make sure that those changes really help to boost conversion rate. We are pleased with results.