Scott Allen has a great blog called Linked Intelligence. He specializes in the Smart Ways to Used LinkedIn. I'll admit, I've sampled the LinkedIn Kool-aid, and I've found it to be a useful tool. (See my other LinkedIn posts here, here and here.)Scott compiled his 2007 top tips into one Linked Intelligence post, and this one post is worth reading:
Best of Linked Intelligence 2007
Check it out, especially his Smart Ways to Use LinkedIn.
The LinkedIn editors got in the act too, promoting an article about Using 8 Tips in Under 8 Minutes.