Large sites have an index or map. Link colours coordinate with page colours. Links are underlined, so they are clear to a visitor. Buttons are not too big. Every graphic has an alt label.
Every graphic link has a text alternative.
Animated graphics turn off by themselves, or better still are not used. Pages download quickly. All pages have good visual impact within a 640 x 460 screen size. Every web page in the web site looks like it belongs to the same web site. Default gray backgrounds.