To work on fundamental softball skills and drills give these drills a go. The first drill that works well for us is the Fungo drill.   The Drop Ball/Quick Bat drill teaches them how to get rid of long, loopy swings.

Fungo Drill
This is a drill where you have players at 1st, 2nd, SS & 3rd.

Have 2 coaches who hit balls.
One hits to 2nd base and they throw to third. Tag throws here.
The other coach hits balls to SS and they throw to 1st working on the plant and throw, no shuffle steps.

In about 15 minutes you can hit 100 balls to the girls.   This is done at every practice, after the first week the girls are wanting more.   They never complain.

This is run very fast and quick.   Everyone is moving at all times.   Each position has 3 girls so they rotate, but they are always moving.     They love it and it is a great workout for the coaches too.

Drop Ball/Quick Bat Drill
Stand with arm extended over the plate from the side with player in the batters box.
As soon as the player strides, drop the ball.

They need to have a quick bat to make contact.   This gets their hands to the ball quickly and gets rid of long, loopy swings.