Dude, I would ignore the rankings stuff. US News and world report, for example is controversial and based on research dollars and whether the school submits the data in the first place and lots of other things that have little to do with either whether the school is good or whether it will take you.
Also, if your credentials aren't stellar and you're flexible (which I guess you are since you're willing to throw appplications at what peope tell you are the worst ranked schools), why only twelve schools? To optimizie your chances and your choice, I would at least double that number.
People's best bets are generally their state schools. You could look at some of those books/sites where they give stats and descriptions of what they're looking for, and pick your best bets that way. And like I said, spread the love, you never know where it might hit home.