TL;DR Make a site with a working database, try to crack it, and then try your best to make it impossible to be cracked the same way again. repeat. GL mofo.
Oh and btw don't be a dick.. If you got the admin's password, good for you.. doesn't mean you gotta log in and fuck shit up for no reason at all.
This is not the type of forum that you come to when looking for hacking advice. I mean, there have been talks of botnets and various brute forcing methods in the past... but nothing notable ever comes from one of these threads. Research other methods, learn various languages, and don't expect to be some kinda all powerful script-kiddie twat.