In addition to functionality, copy, spelling, grammar, and imagery, quality assurance testers can make a huge difference in the success of a web project by focusing on usability.    

Here are some tips for incorporating usability into your QA process:

Start with a clear user flow

Starting with a clear user flow helps to identify any pitfalls the production team may encounter while building a complicated system. Walk through them during the project’s early phases: if you are familiar with a project from beginning to end, there's a good chance you will catch inconsistencies.

Check search functionality and pagination

Paring down search results through the use of filtering and refining should be intuitive and directly relate to the content being searched. If a keyword search produces no results, instead of presenting the user with a blank page, it’s helpful to display copy letting the user know, "Hey we didn't find what you are looking for" or prompt the user to take another action such as an advanced search.

Once you have ensured the search functionality is clear, it’s time to focus on pagination. Pagination labels should reflect the result listing. Results can be listed alpha/numeric order, date, or relevancy, and the pagination should reflect the order. (I recently came across a search results listing in alpha order and the pagination read newer vs. older when the labels should have been “Next” / “Previous” or numbered.)

Pay attention to layout

Page layout should be clean and navigation hierarchy clearly established. Body content is balanced with the imagery and hyperlinks are easily identified. In the case of paragraph headings, is it obvious which heading is associated to which paragraph? If not, spacing may need to be adjusted.

Test form design and validation

Users should be able to complete forms easily and correctly. Error messaging should be presented to the user when required, such as an empty or invalid entry of a field. Many forms out on the web contain no indication denoting a required field and only after clicking “Submit” are you prompted to correct any mistakes.

Know your hyperlinks

Not only should hyperlinks be clearly identified, the user should have a clear idea of where they are going when they click it. Is the message of the hyperlink clearly conveying where it will take the user? Hyperlinks should take you directly to the material you are referencing. If not done properly, hyperlinks will frustrate the user and ultimately lose them.

Closely examine Flash applications

Flash applications rich in complexity (think training modules or videos) require close examination of user experience throughout the entire application. Is the text displayed long enough for the user to read and understand? Is there a static version of the Flash image that will display for users on iPhones and other non-Flash devices? Heavy embedded Flash applications also require you to evaluate performance issues, such as load time. 

Account for a global audience

If you are working with a global site, start by evaluating the copy for US slang and terminology. Pay close attention to form fields for city, state and zip which will not apply to areas outside of the US. If there are plans to localize the site for global audiences, will the copy and design be able to accommodate different text sizes in order to translate to other languages?

Evaluate training materials

Make sure all the steps are included and provide clear instructions to the user for how to accomplish their goals.  Illustrations outlining the training path make all the difference in the world.  Make sure to verify that potential pitfalls in the training path are cleared and that there are instructions for how to quickly resolve any issues that may arise for a new end user.