OK...didn't read all the threads, so pardon me if this repeats stuff.
It's been awhile since my daughter (now 27) went thru the process, but she was our only one, so we went thru alot of research, especially my wife.
First and foremost, what's the personality of your child? My daughter was/is outgoing but she wasn't the real "rah-rah" kind of kid. We had a great visit to UT's honor dept. but in the end, while the school was big, she saw so many kids from her high school and town, she felt that she was almost back in high school. Sports was big for her (she is still a Vol fan though) and neither was the soroity scene. So she ended up going to a small school. Converesly, her best friend, who is like a 2nd daughter, was shy and pretty introverted. She ended up at WKU. Fine school and another big school we visited that really went all out. But sometimes a bigger school can be "smaller". She basically was able to hide in her room and then come home on the weekends. Never experienced college life or friendships. Because the school was bigger, she was able to blend in the background. Now if she had gone to a school like my daughters that maybe had 1000 students (smaller than her HS), her friend would be able to do that. The one thing my daughter had to adjust to was not much alone time. She would park off on a bench to kind of be by herself and before she knew it, poof, 4-5 friends are over there. A shy student would really thrive in that atmosphere I feel.
Next...ACT. My daughter was a very good student and got a number of offers based on her grades and achievements. She took the ACT a second time and got like a 33 or 34 (can't remember) and it was like the floodgates opened up. Suddenly she was getting full rides from all the public colleges in TN and really good offers from privates. ACT/SAT is important. If you find out a school she is interested accepts super scoring, then that's great. You can take your best scores from each section and combine them to make a "super" ACT score.
Lastly visits. They are worth it 100%. We made a number of visits. Once she narrowed down the 3 schools that were her faves, she did overnights. I can't tell you how important those are. Case in point. Her #1 school by far was Rhodes. Not even close. Great school. So we went for an overnight. Well another school she was interested in was Hendrix College in Arkansas (I know...Arkansas). So we arranged the overnights and the Hendrix one was first. We got there and suddenly she was whisked away with a backpack and notebook to a class with a guide. We went to talk to our own guide and went over all the financial, academic, blah blah blah. She was great. Then we go on a tour. Out the window of building I see my daughter in a group of kids making signs for some kind of protest. Laughing and having a blast. She is a bit of a hippy, so this was up her alley. Next morning, we couldn't shut her up about the visit (We left the day before for our hotel knowing this was her school). Next day we go to Rhodes. The person she was doing the overnight was 30 min. late. She finally shows up and takes my daughter. We ended up speaking to no one so we went to our hotel. Next morning we find out the girl she was staying with went to hang with her sorority friends leaving my daughter with the girl's actual roommate. She went to dinner with this roommate and then they came back and watched TV. So the school she was 100% sure she was going to, was dropped off the list. She also did an overnight at Centre College just to make sure, but because of the overnight, Hendrix proved to be the perfect school for her. She got a great education, made lifelong friends, and even her hippy-dippy major (social justice) got her a job. She is now essentially 2nd in charge with the Imagine No Malaria Campaign for UMC. Yes...I'm proud.
Whew...sorry for the long post. Other advice...do a study abroad. It's easy and essentially costs you a plane ticket. Mine studied in France for the sememster and her tuition/scholarships covered everything but the plane ticket...and of course spending money which would be the same whereever.
Thats what I got for right now. Have fun!!