Proofread the content. Your content should be consistent, grammatically correct, and error-free.
Test it using the most popular web browsers. Your website should look and function the same regardless of the web browser you use. We tested ours on Internet Explorer 9, 10, and 11; Firefox; Chrome; and Safari.
Test it using the most popular devices. Your web-browsing experience should be consistent regardless of the device you use. We tested ours on an iPad, iPhone, Android Nexus 7 tablet, and a subset of Android smartphones.
Validate all links. Each link should take you to the right page—whether that’s a different page on your website or an entirely different website.
Validate font and styles. Your fonts should be a consistent style and size, and the look of your website should match the original design.
Validate any site security. Check that every page that’s supposed to be secure—for example, a page with e-commerce, a form asking for sensitive information, or an extranet login—is indeed protected.
Validate all online forms. If your website has forms, make sure you can fill them out and that the submit buttons work. Also double-check that form data is collected and stored according to requirements.
Validate email notifications are sent as expected. Someone at your company should receive a confirmation email for each form that’s submitted. Double-check that everyone receives the appropriate notifications.
Validate that any custom functionality works as expected. For example, the Our Work section of our website is a custom module that had to be tested across several sections of the site.
And much more…Every website is different, and there are more things that could and should be tested.