• Did you validate your (X)HTML using W3C Markup Validation Service?
• Did you validate your CSS using W3C CSS Validation Service?
• Did you check your website in at least IE, FF, Opera and Safari?

Images

• Did you add the ALT and TITLE attributes to all your important images?
• Did you add the LONGDESC attributes to all your image that need a description?
• Did you write effective ALT text?
• Did you make the size of your pages less then 50KB?
• Did you choose the appropriate filetype for your images?
• Did you add a description to images that support your content?
• Did you use plain text instead of images for important content?

Content

• Did you use a sans-serif typeface with a decent font size for your body text?
• Did you adjusted the leading and tracking, if necessary, to increase readability?
• Did you align your body text to the left? (depends on language)
• Did you use EM or percentages instead of PX?
• Did you make sure that there are no whole sentences in uppercase?
• Did you use less then 78 characters, including spaces, per line?
• Did you make brief and precise paragraphs with explanatory titles?
• Did you use lists to sum things up?
• Did you write your conclusion first and then your explanation?
• Did you create enough contrast between the text and the background?
• Did you make your website also accessible for text-only browsers?
• Did you make sure that there are no ‘under construction’ pages?
• Did you include a print function on pages with a large amount of text?
• Did you include a print stylesheet?
• Did you replace all special characters with the ISO Latin-1 codes?
• Did you spell check your content and did you proofread for grammar errors??

Navigation

• Did you make sure that all your links work? W3C Link checker does the job.
• Did you include a link to all your main pages on your homepage?
• Did you include your main navigation on every page?
• Did you use no more then 8 items in your main navigation?
• Did you distinguish the active and nonactive page in the menu?
• Did you use self explanatory link text instead of ‘click here’?
• Did you use self explanatory link text instead of business terms?
• Did you make a distinction between visited and non-visited links?
• Did you make a distinction between links and plain text?
• Did you add the TITLE attribute to all your links?
• Did you use breadcrumbs if you have a large amount of pages?
• Did you include a search option if you have a large amount of pages?
• Did you make your logo link to your homepage?
• Did you make a skip to content link at the top of your pages?
• Did you make a skip to menu link at the top of your pages?
• Did you make it possible to browse your website using SHIFT-TAB and RETURN?
• Did you make sure you didn’t use any javascript links?

Structure

• Did you make a consistent page structure?
• Did you place your logo at the top left?
• Did you place an explanatory tag line next to your logo?
• Did you place your search box at the top right?
• Did you place important content above the fold/scroll?
• Did you make your design on a grid system?
• Did you make your design fluid using percentages?
• Did you make your website also viewable on low resolutions?
• Did you make custom titles (as in TITLE tag) for all your pages?

Forms

• Did you make sure that users don’t return to an altered form after an error?
• Did you make a friendly and informative error page?
• Did you make a friendly ‘thank you’ page with a confirmation email?
• Did you add only a ’submit’ button and no ‘reset’ button?
• Did you tell the user what to expect after clicking the submit button?
• Did you split long forms up into multiply pages?
• Did you gave the user room to type?
• Did you place an asterisk when a field is compulsatory?
• Did you keep the standard look of input fields that is generated by the browser?
• Did you create a logical order of asking information?
• Did you use double input fields for passwords only?
• Did you let the computer, not the user, handle information formatting?
• Did you make sure that users can fill in the entire form using the TAB key?
• Did you explain to the user why you ask certain information?
• Did you explain to the user what you are going to do with that information?
• Did you use realtime validation using AJAX?
• Did you use the LABEL tag?
• Did you place the LABEL above the input field, instead of next to it?
• Did you choose the correct input type for different data?
• Did you make the top input field automatically active using setfocus?
• Did you destinguish the active field from non-active fields using input:focus?
• Did you use the FIELDSET and LEGEND entities when appropriate?
• Did you check if your forms also work with Javascript turned off?

Multimedia

• Did you make sure that essential information/navigation is not made in Flash?
• Did you make sure that music and videoclips don’t start playing automatically?
• Did you make sure that music and videoclips can be turned off at any time?
• Did you inform the user about the size and length of your music and videoclips?

Extra features

• Did you make a custom 404 page?
• Did you make a site map?
• Did you make a rss feed? (if you add content regularly)
• Did you make a high contrast version of your website?
• Did you make good looking URL’s (like this one)?
• Did you make sure that there are no frames on your website?
• Did you make sure that there are no pop ups on your website?
• Did you make a contact form instead of just an email link?

随便baidu或是google一下这个标题，结果一大堆。我认真阅读了每一条建议，受益颇多。如果能在项目开发中认真做到每一点，不但会带来良好的用户体验，同时也对SEO大大有利。我用粗体标出了部分自己觉得现阶段比较重要，且需要在实际中践行的一些条目，提醒自己在实际中能多注意。