Log into your Google webmaster account (http://google.com/webmaster). Your site needs to be registered and verified with Google so you can make changes. From there, go to Search Appearance -> Sitelinks. For more info:
Google Sitelinks is to be considered as a trusted brand, To have a good sitelinks is necessary a good SEO presence and have several people searching for your site daily and have backlink of pages of quality.
Search Engine Ranking and Keyword Relevance
Good Link Structure