2. Avoid having wrong design goals. For example minimizing the number of clicks. To ensure having the proper design goals, know the users, their goals and the context of use. If users are going to your site once in a while on a non-mandatory basis (online banking, news, shopping…), you have to treat them as a novice. They have to understand instantly how to use the site. In this context, it is preferable having a few more clicks and pages with less information. On the other hand, for power user, speed is more important. In this context, less actions, pages and clicks are more important.

3. Do few things and do them well. For example for an e-commerce site, ease of finding the product, having the right information on the product and trust are the key success factors. For a search engine, ease of entering queries, speed and pertinence are the key success factors. Don’t spread your energy on other features unless you master your key success factors better than any others.

4. Design for user limited attention. On the web, many users have little patience and do many things at the same time (they might go on your site while at work). Within 10 seconds, they will abandon if they don’t find what they are looking for. Since the reading speed is about 200 words per minute, you can provide a maximum of 35 words to read before a user abandons. So minimize the quantity of text. Contrary to TV where the full screen is in use, on a computer, only a small portion of the screen is viewed simultaneously (roughly 6 to 7 cm diameter). This is due to the useful field of view, which corresponds to the subtended angle of the fovea vision. Information must be grouped within this diameter. That’s why banners are so ineffective. For most page layout you can afford about 4 to 5 groups. Avoid long lists of items, users read only the first few items at the top of the list. Organize according to the natural eye path. Remember users start from the top left corner, go to the center and if they don’t find what they are looking for, then they try to go to the left expecting a menu. For this reason, avoid menus on the right. The bottom right is the worst real estate of a page.

This sketch show the typical eye pattern on a web page.

5. Avoid relying on branding. Users do not remember seeing your ads, brochure and other corporate information. Keep your brand simple and name your entire product line in relation to a user goal. If you already have a brand for a product, provide a prompt matching the user goal. This also help SEO (Search Engine Optimization). For the same reason, you don’t need to be that consistent between corporate brochure and web site.

6. Users don’t read, they scan. Users will scan text and when they find something that is likely to meet their goals, they click on it. You better to expect that users won’t read your text. A good approach is to provide just a list of hyperlinks with a large font. You can also provide a small description with a maximum of 15 words with smaller lighter font under the hyperlink. This technique is ideal for a newsletter. Users will scan the list, if they are interested, they will click on it and read the description under it.

7. Ensure users understand your text and graphics. At least 50 % of the usability problems are related to the wrong choice terminology. Users get easily confused between concepts such as events and news, schedule and time table…. Minimize the number of concepts. Don’t worry, users mix apples and oranges. Test and test again your site with real users to find the right terminology.

8. Don’t reinvent the wheel. Use basic web controls. You don’t need to create complex navigation structure. A simple menu and the browser’s back and forward button are Ok for most of the cases. Once users have a successful behavior, they continue to us it for other goals. For example, if they find something through the menu, they will try this method again for another goal. Limit your design to familiar controls. Use straight hyperlinks to select a page. You will make more money with blue underlined hyperlinks because the users’ reaction time is about 30 ms less.

9. Use readable font. If users find the information and can’t read it, it’s zero. Why using small fonts? If your fonts are too small, only younger users will be able to read it. With the right size, everybody will be able to read it. Fonts must have a size equal to 1/200th the distance of reading for proper readability. On a computer screen, fonts must be at least 3 mm. For example MS Sans Serif or Verdana at a minimum of 11 points are Ok. Font adjustment controls don’t work because most users that would need them never use them. Those having serious reading problems already have special adjustments on their browser.

10. Be permissive to errors. Users make errors. The best way to manage errors is to allow them. For example, be permissive to various date formats. On the other hand, if users make errors, ensure proper detection, recovery and simple messages. Messages must have two items: the status and the corrective action.

For more information , you should check the Top 10 Web Design Mistakes of 2003 from Jacob Nielsen

On this Montreal picture, you can barely see the streets signs.

Montreal street names are poorly located and the font size is way too small.
How many car accidents happened as a result of this?
I wonder why city planners do not seem to known the law of font size.
n Montreal, this rule is violated everywhere: billboard signs, parking signs, print documents, etc.
How the heck can someone read the Montreal street signs?
What should be the font size for normal readability?

The answer is: 2 X Tan (0.3 degrees/2) X reading distance

The angle that provides good readability for 95% of the people is 0.3 degrees. For a reader at a distance of 60 cm it results in a font size of 3 mm. For a reader at 50 meters, it is 25 cm or one foot. A good approximation is roughly 1/200 of the distance. Montreal city road planners should learn from SanFrancisco.

On this picture, you can see there is a much bigger Mason street sign on a green background.
Note that this sign has been added over the small one.
The legibility rules are respected: Mix and San Serif fonts on green background and a size above one foot enough for 50 meters distance readability.

UFOV 

It is the single most important concept in effective screen and web page design. It is at the essence of human attention, a central issue in Cognitive Engineering.

What is it?There is a small area in the retina that provides the clearest vision of all. This vision is also called the central vision or foveal vision. It corresponds to a spot making an angle of 3 degrees.   So for someone sitting in front of a computer screen, the size of the spot of visual attention is about 4 cm.  For someone standing behind the shoulder of somebody else in front of a computer screen, the size of the spot is about 8 cm. The spot is about 24 cm when watching television at a normal distance. So somebody standing just behind you will have a broader spot than you and will be more likely to find the information your are looking for on the screen. 

Increasing Sales

In the example above, if information is outside the UFOV, it will not be recognise or perceive. Consequently, if you place adds anywhere, they will not be effective because they are likely to be outside the UFOV. Knowing what users are looking is a fantastic insight when combined with the UFOV notion. A designer can suggest new cross-related option (or add) and present them inside the UFOV.  

Google

This concept is simple and effective and it explains why Google’s Add is so successful.Why not do the same?