"If your site's structure doesn't allow our algorithms to find good sitelinks, or we don't think that the sitelinks are relevant to the user's query, we won't show them. However, we are always working to improve how we find and display sitelinks." How do i know if my site allows google's alghorithms?
No one exactly knows, but those sites with sitelinks already achieved some kind of being an "authority site".
maybe try to search for your most competitive kw/s or maybe search for your domain name.. it usually work that way..
I don't think even Google is sure about its sitelinks algo, or the algo is not stable . My site some times has few sitelinks, some times has no sitelinks. Very unstable!