There is no need to ever run out of things to test on your website if you are in a market that has at least a fair amount of competition. The competition will give you plenty of things to do and not do.

When you find something on a competitors site that you don’t have, make a note of it and test it. You never know when you will come across something that will make a huge difference to your bottom line.

Here is a list of things to test, some will be relevant to your site some will not:

Images
Offers
Price scenarios
Calls to action
Bonuses
Page layout
Emotional appeal
Headlines
Storylines
Deliverability options
Service options
Upsell
Downsells
Shipping Options
Site searchability
Security seals
Colour schemes
Navigation
Email capture mechanisms
Free report offerings
Form layout
Communication formats
Telephone number display
Product layout
Descriptions of product
Buttons (size, copy, colour)