Five main guidelines for links

Even in a promotional context, I wouldn’t recommend using “click here” links, or “read more” for example. Here is a quote from Jakob Nielsen about links (I know, I know.. we can’t consider every word that Jakob says):
 
“Following are the five main guidelines for links:
Make obvious what’s clickable: for text links, use colored, underlined text (and don’t underline non-link text).
Differentiate visited and unvisited links.
Explain what users will find at the other end of the link, and include some of the key information-carrying terms in the anchor text itself to enhance scannability and search engine optimization (SEO). Don’t use “click here” or other non-descriptive link text.
Avoid JavaScript or other fancy techniques that break standard interaction techniques for dealing with links.
In particular, don’t open pages in new windows (except for PDF files and such).
Links are the Web’s number one interaction element. Violating common expectations for how links work is a sure way to confuse and delay users, and might prevent them from being able to use your site.”
 
http://www.useit.com/alertbox/designmistakes.html
 
The Sun’s usability team tested their website and here are their comments: http://blogs.sun.com/MartinHardee/date/20040916 . They concluded that ” “Click here” is so bad because it forces the eye away from the important content.”. Other tests got the same result.
 
Of course we know that for every rule we have exceptions. But if you can make the link more relevant it will be better than using vague links.
 
So, if you have a promo banner or minisite, maybe you should try using clear actions like “buy now”, “register”, “apply” or something else that represent what will happen if the user “clicks there”.
 
Hope it makes sense!