1. Try not to exceed 10-12KB per image. There is nothing worse than a website that is painstakingly slow, and using huge images is the primary cause. Not only that, the best websites are almost always clean and clutter-free, and using massive in-your-face images is the first step to a non-functional and visually unattractive website.
2. Your images should nearly always fit the content. If yours is a corporate website in the healthcare sector, avoid images of animals or sports, unless the content deems it appropriate. The only exceptions are design images, or images that are incorporated as part of the web design process which make up the overall structure of the page and are not intended to illustrate the content.
3. Flashing or blinking images are as annoying as the common cold. Use moving images sparingly on your website, and when you do, try to locate them in inconspicuous spaces or out of the eyeline of the content. Moving images are not the substitute for poor content management, and they are best used to compliment the content rather than replace it.
4. Standard layouts are standard because, believe it or not, they work. Sometimes being different just doesn't work, so avoid brief novelties such as side-scrolling websites and 6 or 8 frames on one page, and stick with a popular 3 column layout which is simple and easy to navigate.
5. Often looking at what isn't there is just as important as what is there. Whitespace is a crucial component of your layout, and the choices you make about your whitespace will inevitably effect how the rest of the site will look, so don't neglect it.
6. As we have already discovered, graphics in the form of design images don't have to be divorced from site layout. Design images are an element of your layout structure, and using them in this way can make them more than just graphics. Merging graphics and layout is a sign of not only a good website design but a good designer.
7. You can play it safe by using Serif fonts for headlines and Sans-Serif fonts for text. Although not a popular choice in print design, Sans-Serif fonts are much easier on the eye because screen resolution is not as high as in print. Be careful not to use Serif fonts for normal text, however, as the Serifs can look blurred on the screen making them unecessarily hard to read. It's handy to use the opposite fonts (Serif for headlines and Sans-Serif for text) for your printer friendly page.
8. The first sign of poor website design is a multitude of contrasting fonts. Try to limit your pages to 2 standard font families, making your site look more professional and therefore improving your chances of getting repeat visitors.
9. Only use standard font families, the common fonts which people use day-to-day. Not only will it look more appealing, but the chances of all users having a more uncommon font are relatively slim, meaning your website will look plain and boring.
10. It's easy to go overboard with the amount of ads on your site, but you should always remember that people are visiting for the content, not the ads. A sure-fire way to drive people away is to drive them away with a bombardment of sales-heavy ads, and even the best content in the world wouldn't make them hang around.
11. The same rules for images apply to ads. Keep them small, static and suitable. Ads are more likely to succeed if they fit with the overall layout and atmosphere of your site.
12. Test, test, test and test some more. Your site should work on all modern browsers, and if you don't test it on these browsers, some visitors won't be able to view your pages.
13. Repeat the above for operating systems. Testing between Windows and Macs is pivotal to ensure your site is available to the maximum potential audience.
14. It's more than likely that your visitor has arrived at your site because they have been looking for something that you provide. Therefore, make sure your site delivers on its promise and offers them the content that they require.
http://www.design-logix.co.uk/blog/blog-entry/top_tips_for_web_design
