Do you know what areas of your home page get clicks? How about what pages nobody scrolls down? Heat maps help you make the most of your store layout.
Locally or globally, paying it forward is appreciated by potential customers. And it isn't hard or expensive to set up.
Turn your transactional emails into a standalone sales channel and see repeat business spike. Leave no stone unturned when it comes to ways of increasing your conversions, especially if they can be processes that tick over nicely all on their own.