For an example of what I mean, search on Google for "Last.fm". The first result will be www.last.fm and 8 additional links are listed; "Listen", "Log in", "Music", "Download", "Charts", "Sign up", "Jazz music", and "Users". I looked around in their HTML but couldn't figure out where this information was supplied to Google.
Any help? Thanks :)
You can try looking at the Google Webmaster Tools, and provide google with a webtree of your site.
Write semantic markup.
Google work out the important links from that, they aren't told explicitly.
Google's documentation explains the process.
Use XML sitemaps. However, be warned that sitemaps must not be misused. There is a big debate on whether sitemaps are good or not.
The above answers are all good.
You might also try NO FOLLOWING (rel="nofollow") unimportant links on your homepage or other pages. Google will the give more weight to the followed links.
It used to be that you needed to be pagerank 4 or higher to get the sitelinks to show up if you were the top result. (and then you could edit them via webmastertools)
but it seems like google are currently changing things around. apparantly they were not clicked enough to warrant taking up valuable space on the resultspage.
I met such thing before. What I did is submitting new, accurate site page to google.
Taking a close look at the content, as well as Mata tags to see if they are accurate and descriptive. In my case I reorganized the whole content.
Most important, I back to the track of SEO, refresh content frequently. Shame to me, I had not refreshed content for a long time.
I do not know which one plays the rule, but thing works pretty well now. Hope it it is worthwhile for you as a reference.