It's more like finding a job than anything:
They have a position and you want to fill it. You have to be one of the best options they have at that position. They are going to look at the complete package...academics, athleticism, desire, work ethic, morals, family tradition. There is a little bit of sizing up for potential but I think most colleges are looking for a guy who's ready to play at that level or very close. He can manage his academics with the demands of the team.
As a pitcher, they want strikes and pitch count management. Let the defense they recruited make the outs. Of course they'll take the strikeout but the truth is it takes more pitches than a groundout early in the count.
There's really so much more to it that there are businesses based on the whole service of assisting in getting a college fit for you. Personally, I think you can do it on your own for a fraction of the cost.