Therefore you should make your pages no wider than 640 pixels. You can assume that users may have a smaller screen size, but because of the many 13-inch monitors in use, you can never assume that a page can be bigger than 640 pixels by 480 pixels. Some people might even be using a PDA such as a Newton MessagePad to view your Web site. Many people don't realize that they can scroll down a page, so it is essential to put critical information into the first screen full that people see when they open a page. Design for Different Page Orientations Because users can change the size and shape of their web browser windows, you should check your page layout in different configurations to be sure that it works well however the user views it.
Most browsers have a default appearance for unread links and links that the user has already viewed.
Because users rely on the consistency of the interface to help them navigate and use the Web, it's best not to override these settings by hard coding an appearance for links in your site. If you do find a compelling reason to override the appearance of links, do so consistently throughout your site. Don't capriciously change the appearance within your site. Use white space around headings, graphics, and paragraphs of text to create a sense of balance on the page. By providing relief, white space can neutralize the effect of two competing elements of the same size that draw the eye back and forth across a page.