• Emphasizes function over form : When a user visits a website, she usually wants to obtain information or perform a task. The more difficult your site is to browse, the more likely the user is to move to another site with better browsing. 

Animations and blinking bits come and go, but what remain are sites that have basic information presented in a professional, easily accessible manner. Using the latest cool animation software or web technology makes me think of the days of the HTML <BLINK> tag. The <BLINK> tag, for those who never saw it in action, caused the text within it to disappear and reappear on the screen. Nearly all web developers seem to hate the <BLINK> tag and what it does to a webpage. Those same developers would be wise to keep in mind that today’s exciting feature or special effect on a webpage will be tomorrow’s <BLINK> tag. Successful websites stick to the basics and use these types of bits only when the content requires them.

Use elements like a site map, alt tags, and simple navigation tools, and don’t require special software or plug-ins for viewing the site’s main content. Too often, I visit a website only to be stopped because I need a plug-in or the latest version of this or that player (which I don’t have) to browse it.
Although site maps, alt tags, and simple navigation might seem quaint, they are indispensable items for accessibility. Text readers and other such technologies that enable sites to be read aloud or browsed by individuals with disabilities use these assistive features and frequently have problems with complex JavaScript. 

• Follows standards: Web standards exist to be followed, so ignore them at your own peril. Using a correct DOCTYPE declaration and well-formed HTML helps ensure that your site will display correctly to your visitors. Validation using the W3C’s Markup Validator tool is highly recommended. If your site is broken, fix it!
• Renders correctly in multiple browsers : Even when Internet Explorer had 90 percent market share, it was never a good idea for programmers to ignore other browsers. Doing so usually meant that accessibility was also ignored, so people with text readers or other add-ons couldn’t use the site. People using operating systems other than Microsoft Windows might also be out of luck visiting those sites.

Although Internet Explorer is still the leader among browsers used by web visitors, it isn't the only browser your web visitors will use. Somewhere around 3 or 4 of every 10 visitors will be using a different web browser.
You never want to turn away visitors because of their browser choice. Imagine the shopkeeper who turned away 3 of every 10 potential customers just because of their shoes. That shop wouldn’t be in business too long—or at the very least, it wouldn’t be as successful.

If you strive to follow web standards, chances are that you’re already doing most of what you need to do to support multiple browsers. Avoiding the use of proprietary plug-ins for your website is another way to ensure that your site renders correctly. You need to look only as far as the iPad to see a device that is popular but whose use is restricted because it doesn’t natively support Flash. For this reason, creating sites that follow standards and avoid proprietary plug-ins ensures that your site is viewable by the widest possible audience.

• Uses appropriate technologies at appropriate times: Speaking of plug-ins, a well-designed website doesn’t overuse or misuse technology. On a video site, playing videos is appropriate. Likewise, on a music site, playing background music is appropriate. On other sites, these features might not be so appropriate. If you feel that your site needs to play background music, go back to the drawing board and examine why you want a website in the first place! I still shudder when I think of an attorney’s website that I once visited. The site started playing the firm’s jingle in the background, without my intervention. Friends don’t let friends use background music on their sites.