Last month, Google announced new and extended sitelinks. The maximum number of sitelinks increased from eight to 12:
Last month With Google's new sitelinks, the meta description tag becomes more important.
Google generates the sitelinks for your website based on your website navigation and based on the links that point to your website.
Google uses the first 30-35 characters of the meta description tag of a web page for the snippets.
To increase the number of clicks on the snippets, you should optimize your meta description tags:
Note that Google updates the sitelinks of a website periodically. It may take some time before the new descriptions of your web pages appear in the sitelinks.
- The first 35 characters in the meta description tag should contain a clear description of the page and/or a call-to-action.
- Each page of your website should have its own meta description.
In general, Google shows sitelinks if it is sure that a website is the exact match for a search query (usually product name or company name searches). Google generates the sitelinks for your website based on your website navigation and based on the links that point to your website.
If Google does not show sitelinks for your website then you should work on your website navigation:
Source: Points taken From an Article http://www.free-seo-news.com/newsletter489.htm