1. Network....talk to as many college coaches as you can. Go visit them in your downtime to shadow for a day, and see what office work and recruiting is like.
2. Find a way to prove you can recruit.....college is about recruiting first, coaching somewhere after that.
3. Be able to sacrifice.....if you can't volunteer then you might be out of luck.
College coaching isn't about who is the best coach. There are coaches that can improve athletes at every level. The best coaches know that the most naturally talented athletes make coaches look the best.....it ain't about coaching. It is about attracting that talent to the school you work for. So high school coaches looking to coach in college are at a disadvantage because recruiting is THE thing, and you just aren't gaining recruiting experience while teaching HS physics and coaching on the side.
To get in, you need to find a way to prove your worth. That usually means working for free or part time and then doing all of the crap jobs around the office, and FINDING A WAY to learn and help in recruiting. Be the guy that gets the contact information on the most talented kids and give it to the coach for that event area.....then ask in return, to be copied on any emails or to sit in on some recruiting calls to see how it is done. Then be valued added when the kid and family visits campus. Drive the van, rake the long jump pit, set up the cones, be thankful to take splits for the slow group.
And don't expect to see the same results with the same coaching methods from HS to college:
#1. It is college, kids live on their own, make different choices about eating, sleeping, socializing, and how important the sport is. So when HS coaches say "college coaches can't develop kids like I did,"it isn't always the coach.
#2. HS kids are often a blank slate, and with the vast majority of those with limited talent, the ceiling can be nearly reached in 4 years......there just might not be much left for the college coach to do......then add in #1 and one quickly finds that HS and college "coaching success" are apples and oranges.