Question: What are major things coaches look at when they come watch you play or consider signing you?
Answer: Coaches differ in what they look for in a player, so it's next to impossible to generalize. All coaches try to assess a player's energy, enthusiasm and work ethic, and all coaches want to recruit the most athletic players they can. But athleticism as well as ability, experience and skill level will vary tremendously from one athlete to another. And what the coach at a Top 25 Div. I program expects/demands from his or her prospects will usually be somewhat different from what the coach at a small Div. III or Junior College might look for.
If you watch college softball on the Internet or on a TV sports network, you'll get an idea of how incredibly athletic and strong players at a school like Arizona or Florida State are. So, to be considered a prospect for that kind of college, you have to really be a top athlete. However, since 75% of colleges aren't Div. I, most players will be more likely to appeal to coaches at Div. II, III or NAIA teams.
Your overall athleticism and your fundamental softball mechanics---e.g., your swing, your fielding skills, etc.---as well as your understanding and knowledge of the game will be important to most coaches. And depending upon what position you play, other aspects may come into play. Catchers need different strengths than pitchers. Infielders need different skills than outfielders. An outfielder would need to demonstrate speed, range, a strong arm, the ability to read the ball off the bat and so on, while a first baseman might be assessed based on her height, ability to stretch and to scoop the ball, etc.
In general, if a college coach is coming to watch you play, you want to show that you're serious about the game and work hard at it, but that you also know how to keep things in perspective. You don't sulk if you miss a ball or strike out, you try to learn something from every game you play, you give 100% all of the time, and you do your best to be a supportive teammate. For more information on the college search process, consult my book, Preparing to Play Softball at the Collegiate Level.