What is on the site? It is imperative that you are fully aware of what your online audience needs. Special considerations and accommodations are required when designing Web sites for maximum senior usability. The National Institute on Aging and the National Library of Medicine collaborated on some basics for “Making Your Web Site Senior Friendly.”
Here are some of the tips on their checklist, as well as additional design best-practices:DO use an easy-to-read, sans serif font–such as Arial or Verdana–in medium or bold, and in upper- and lower-case letters.
Offer a printer-friendly version of the page.

DON’T use serif, novelty, condensed or all-cap fonts.

DO keep page copy brief.

DON’T make readers scroll. The ability to scroll a
Web page is not only a learned behavior, but one that also
requires a level of dexterity and coordination your visitor may not have. If you can’t avoid scrolling, consider creating your own, larger scroll buttons on those pages.

DO provide an obvious way for visitors to increase text size
with a simple click of their preference.

DON’T go smaller than 12-point text.

DO use dark type against a light, plain background.
View your site through a yellow filter to simulate certain
age-related vision problems and make sure it maintains its
clarity, contrast and legibility.

DON’T use yellow, blue or green close to each other–and avoid reverse type and patterned backgrounds. They make your content harder to read.

DO make links obvious and consistent. Image-based links should be large and easy to click. Let visitors know what’s clickable–and where they will go or what will happen when they click.

DON’T use Web lingo such as “back,” “URL,”
“toolbar,” “IM” and “minimize,” or icons, without a clear
explanation. And don’t use drop-down or tree menus.
They’re confusing. According to Fidelity and AARP studies, most seniors are not familiar with commonly used Web terms.

DO keep your site simple and stable. The rest of the Internet may need to change all the time to maintain its appeal, but sites for seniors should remain familiar and change gradually.