I would like to know what back links does the site that rank 1st is coming from
There's no way to know all of them because Google doesn't report all them (except possibly to the site owner in webmaster tools). Yahoo site explorer will show you links to another site but I don't believe it is complete either nor does it have nearly the same volume of links as Google does thanks to Google's larger index.
if possible what are the different strategy they have done
There is no such thing as a "SEO strategy". SEO is just a well built website. If you have a strategy then your website is probably broken and you are focusing on the wrong stuff.
Any tips on what I need to do to proceed? I have done all the basic stuff, ranging from meta tags, title, h1, update your site regularly, keep it clean, relevant, useful, no errors on the page, submit sitemaps, social bookmarking... what else am I missing here?
This has been covered here already.
Just focus on continually improving your website and marketing it (getting links is marketing). And be patient. It takes time to rank well especially if the terms you want to rank well for are competitive.
Free seo tools for competitor analysis?
How should I study a competitor's off page SEO?