My choice was back in the day, and "clueless" describes it fairly well.
I basically applied to schools/programs that I had heard of. [I only received unsolicited mail from *one* college, Michigan State--they had some kind of special scholarship that they mailed me info about. I didn't apply, mostly because I had little interest in going "Back East" for college.]
Having lived in Washington State and then El Paso for some years, I applied to UW and UTEP; having grown up in the West and heard that Stanford, Caltech, and Deep Springs were good, I applied to those. My older sister had won some sort of national writing award, so she received info about a special six-year (UG+Grad) Ph.D. program that was hosted by an Ivy, and I applied there too, though I didn't think I'd get in.
I was accepted pretty much everywhere--it was some years later before I learned that I would have been accepted by every college except women's schools and the military academies--didn't hear from the six-year thing so I deposited with Caltech (easy choice over Stanford, though I did get a great financial-aid offer from The Farm). Then on the last possible day I got a telegram about being accepted for the 6Y thing and, after a couple of agonizing days, decided to forfeit the Caltech deposit and ended up at the Ivy.
In retrospect I think the deciding factor for me was just how difficult/exclusive admission to each college/program was. I really didn't have a clue to things like academic quality. For instance, I thought Penn State and Harvard were basically the same: two big Eastern schools that I'd heard about; and to me the Ivy League only meant a "locker loop" on the back of your shirt. Athletic programs were not a factor at all and economics played no significant role (I would have ended up with about the same bottom-line expense everywhere). So I basically joined the club that was most reluctant, or so it seemed, to have me as a member.
BTW during the whole application process the only colleges (of those listed) that I'd actually seen were UW and UTEP. The first time I saw the Ivy was the day before classes began.