One of my favorite softball practice drills is the half-size field backup drill.
The set up for this softball drill goes like this. Make 2nd base on the pitchers mound, bring in 1st and 3rd halfway, and have the outfielders stand on the edge of the grass/infield.
Give the kids a scenario (man on 1st, 1 out) and then roll the ball to a player. Everyone else should be moving to a spot – either covering a base or backing someone up. This gets the players thinking about where the softball may go, where the bad throws would end up, and the geometry of the backup (get in line with the thrower and receiver, and stay 15 ft back to have a good chance of backing up the play).
I also divide my kids into even teams and have them do infield as a contest. I hit the grounders. The kids on one side try to beat them out, each “safe” is a point, each “out” is a point for the other side.
Kids love competition, and this also puts a runner into an infield softball drill, adding some pressure.