Sighted keyboard users generally navigate through the links and form fields on a web page using the Tab and Shift+Tab keys on the keyboard. To help ensure they can visually identify which link or form field they have navigated to, you can add the following to your CSS file:
a:focus {
outline:1px solid red;
background:yellow;
}
The colors may need to be customized to fit your site design, but they should be fairly distinctive.
To take this tip one step further, you can search your CSS files for a:hover and in each instance change it to a:hover, a:focus. This will ensure that keyboard users get the same visual highlighting when they navigate to items as mouse users get when they hover over an item.
"Today is Global Accessibility Awareness Day (GAAD). To celebrate and to help promote accessibility, here are 10 simple accessibility tips that most anyone can implement today into their web site's HTML and CSS to make it more accessible."