I haven't taken the time to read all of the responses, so forgive me if I am repeating anything.
DD is just finishing up her freshman year of college, so this is all pretty fresh for me.
First of all... save what you can (obviously). We did NOT save enough.... not even close. Should have started sooner and been more disciplined, but can't go back in time now. Some of that was due to real life expenses, some of that was due to poor planning and execution on my part. We are paying for what we can OOP and DD is getting some loans. We told her we woul help her with the loans when the time came and we will do our best. We are working now on putting her work study money into paying for the unsubsidised loan that is already earning interest.

Have your child start asking for money and bonds for holiday and birthday gifts and stash it away..... $25 here and then for the next 4 years will definitely add up!!
We told DD to apply anywhere/everywhere she wanted and we would worry about the $$ after the fact. She applied to about 5 schools.... all private, varying sizes, a few ivy league. She only got one "no" from an ivy league school that we knew would be a reach. She was offered scholarships (merit based) from all of the others, of varying sizes. We didn't know enough at the time to use them to negotiate with each school.... we were just happy with what she was offered, since we qualified for virtually NO financial aid.
She was a 4 year varsity athlete, but knew that she wouldn't be a walk-on for Division 1, so she decided on a Division 3 school where she was assured a spot on the team by the coach. After dedicating 10 years of her life to this particular sport, we never imagined that she WOULDN'T compete.... but lo and behold, the team was NOT what she was hoping for and after two months of struggling to make it work, she stepped away. It was one of the HARDEST decisions I know that she has ever had to make in her life.... but I thank GOD every day that she wasn't there on a sports scholarship! That would have made a difficult decision nearly impossible!
Despite "talking the talk" of "you are a student first and an athlete second" the team and the coach did not "walk the walk" and DD was constantly struggling to make it to classes on time after morning practices (the coach was always keeping them just a bit too long), to connect with teammates who, it seemed, were there for fun and parties much more so than an education, and to find the time to fit it all in (double practices, a full course load with labs and homework, plus a few hours of work study). She was stressed and exhausted and miserable. Again, I am EVER so relieved that she didn't have any scholarship money riding on the sports. In fact, she was concerned about not getting the grades to keep up her merit scholarship if she continued on the team. Her professors were able to see the steep rise in her grades as soon as she quit the team and they told her so. She hasn't regretted the decision to put the emphasis in college on LEARNING. She knows that that is the right decision for her and her future.
Just want to emphasize... she KNEW going ito this that sports would take up a big chunk of time.... but as a club AND varsity athlete for all four years of high school, plus maintaining an "A" average, she certainly KNEW what was involved time-wise in maintaining this... but there was SO MUCH other stuff outside of normal practices (weekends spent hosting recruits, team community responsibilities such as fundraising for national organization) and the lack of emphasis from the coach on the importance of making it to classes consistently and ON TIME, plus the attitude of her fellow athletes, that made this a difficult situation for her. And some of the PERKS for athletes that others have mentioned certainly didn't apply at my DD's school..... for example, there was no dining hall option for a meal before an early morning practice.... and the coach let them go so late that there was rarely time to stop at the dining hall after practice/before class..... so if we didn't provide DD with some food for her room, she didn't eat! How can you tell an adult athlete with a 2 hour practice that they can't eat??? And we are paying for a full dining plan (as required for freshman) so breakfast was a meal that we paid for every day but weren't able to get.
As far as things to do BEFORE the college application process starts.... BE INVOLVED (second only to getting good grades!). DD spent SO MUCH time on her sport and grades, there wasn't much time to be involved in anything else. Thank heavens that she decided in 8th grade to become part of the Rainbow Girls! It gave her something besides a sport and honor societies to put on her applications! She was an A student, in multiple honor societies, top 15 of her graduating class of 200-ish, 4 year varsity athlete, NH Scholar Athlete, senior year all school-science award winner, outstanding scores on her SATs and ACTs, considered for a National Merit scholarship, AP student, etc.... but without those EXTRAS to put on her applications, they would have looked blank!! Be sure that your child gets involved in at least ONE activity outside of sports and academics.... theater, music, community service (such as scouting, volunteering, Amnesty Int'l, Leo club, etc), and stick with it for the next 4 years! Colleges want to see that you can handle more than just academics and have a balanced life.
DD didn't take any legit "college" courses during high school, but was able to place out of English and two semesters of college biology based on her AP exam scores..... but that being said, we are now being told that some Master's programs do NOT accept AP credits and she may be forced to go back and take the biology classes any how.

But we will cross that bridge when we get to it. Since DD was able to get credit for so many classes, she was actually considered a Sophomore after her first semester, so that bumped up her lottery number for housing and class selections, so that was a nice perk. And it will allow her to have a bit more "free" time in her schedule to lighten her load during a study abroad semester (or two!).
All of that being said..... I also have a DS who is a sophomore in high school and he is a WHOLE DIFFERENT kettle of fish!! I will be encouraging him to stay at home for at least a year and attend community college. He is heavily into robotics and wants to be an engineer, but isn't the dedicated student that DD is. We have an in-state college that has started offering a two year degree in robotics and I think that is a great first step for him. That being said, he WILL graduate HS with some college credits, thanks to Project Lead The Way and his mom's checkbook!

I could even see the potential for him to get a 2 year degree in just 3 semesters, if he buckles down over the next two years.
Best of luck to you and your student!........P