A lot of my girls have a hard time getting their hands inside the ball when they hit. The goal of this drill is to drive the hands forward and through the ball, not to pull out away from the ball.
A good drill for the hitter is to put the knob of the bat on their belly button and the end of the bat on a wall, fence, net, etc. From that distance, get in your stance and swing.
If the hitter is bar arming, they will make contact with the object they are standing in front of. One thing to watch is that their front hip does not open too fast. Attack the ball by keeping your hands inside.
This is a great drill for the hitters to visualize driving their hands to the ball.
Plunger Hitting Drill
One of the hitting drills that we have used in the past, to help force our girls to follow through is by placing a plunger (new) upside-down in the tee and placing a basketball on it.
It really shows the girls that they need to get there lower bodies involved in their swing and that they need to finish the swing.