Traditionally, links are underlined as well, but that approach is often unnecessary and falling out of favor to reduce visual clutter.
Links lack affordance, which means their visual properties don’t suggest how they are used and are understood only through experience.
Link text should indicate the result of clicking on the link.
Use different colors for visited and unvisited links.
Don’t use color for text that isn’t a link because users may assume that it is a link.
Always show either an underline (for any link text) or a button frame (for command link text only) on hover to reinforce visually that the text is a link.
Don’t underlined text that isn’t a link because users will assume that it is a link.
Use background colors that contrast with the link colors.
Use link text that is the most relevant part of the text and are large enough to be easy to click.
Don’t provide an infotip [in HTML, a title element] that is merely a restatement of the link text.
If a link requires further explanation, provide the explanation in either a separate text control or an infotip, but not both.
Place optional supplemental graphics that indicates the target of a link to the right of the text and use an infotip to explain its meaning.
Link to specific content rather than general content.
Use a link only if the linked material is relevant, helpful, and not redundant.
Link only on the first occurrence of the link text.
Don’t add “Click here” to the link text. It isn’t necessary because a link implies clicking. Also, “Click here” and “here” alone are poor link text because they convey no information about the link when read by a screen reader.
Start the link with an imperative verb and clearly describe the action that the link performs.
Don’t use ending punctuation except for question marks.
