my competitor run a site, build/buy quality links to both home and inner page, google give it sitelink. but my site has not sitelink and build most links to homepage. but my site exceed his for most keywords. LoL Rank is rank. Anthority is another thing.
Sitelinks have nothing to do with any mythical 'authority' status. Google provide them as a help to searchers when the structure is appropriate, not as a reward to webmasters.
Some one who well known on DP said, build deep link will help authority. my competitors build many QUALITY deep links, target inner page not homepage. it seem it got authority too. but his rank is not good than mine.
There is no such thing as 'authority' - it's a slang term, it's not recognised by google. It has NOTHING to do with sitelinks
I have a site that has site links. From what I can tell it's because the internal pages have a lot of related links pointing to them. The site links aren't the pages I would pick, but because other people have given those pages back links they end up being in the site links. So try to get some good back links the the pages you want as a site link and it should help.
Basically SERP = relevancy x popularity x trust. All of them have something to do with backlinks. Weaker backlinks can be somewhat compensated by better onpage relevancy and site age. Each page/site ranks by complex score that incorporates number of factors.