Hat-in-Mouth Drill
I used a similar drill to this in my first few years coaching, but after talking with Dennis Markiewicz, the varsity coach at GHHS, he demonstrated this for me, and it is a simple and easy way to teach proper fielding of ground balls.
You can have the players in one line or several, depending on how many coaches you have.
1. The player in the front of the line should flip his hat around and put the brim in his mouth.
2. When you say go, the player should begin to creep up as if "rocking into position."
3. Roll the player a ground ball; he should shuffle his feet so that the ball will play directly between his legs.
4. When fielding the ball, the player must be able to see his hands - to do this, he must extend them beyond the length of his hat in view.
5. Once the player fields the ball, he should quickly pull it up to his chest and square his legs into a throwing position.