Think of your users first and the context in which they are using your site:
Success in interaction design is largely a matter of following established patterns, so people can apply what they already know to new contexts. Using known and well-established interactive controls goes a long way in designing for easy interaction. There are specific considerations that will help make controls more usable for people using assistive technologies. And there are design considerations that make interaction more usable and enjoyable for everyone, including people with disabilities.
(via A List Apart)
If you're interested in providing the best experiences for your client, join us Thursday Sept. 4 for a panel discussion on usability testing.