Take a look at this submission from Mike.   A great example of a [tag]softball sliding drill[/tag] that can work with all age groups.  

Softball Sliding Drills

When my practice begins all players arrive 15 minutes early to play catch.   I indicate to them that it is essential that they not be late because that is the most Important Part of their practice.   I use that time to set up the field for other drills planned for the day.     They take this warm up time very seriously.     I ask them periodically “Girls do you know what the most important part of our practice is going to be today?”   They repeat in unison, “The first 15 minutes.”     Nobody is ever late because one of their teammates would not have anyone to throw with and it’s the most important part of   [tag]softball[/tag] practice.   I remind them that every play in softball involves a throw and a catch.
I then follow this up Every Practice with 5 quick minutes of [tag]Sliding[/tag] Practice.   I have found in our league that girls are hesitant to slide.   My team does not hesitate because they become so proficient at it.     They all line their gloves up along the left field foul line in the outfield spaced about 4 feet apart.   They line up about 60 feet from their respective gloves and I begin at one end of the line and say “Go!”   The first girl runs full speed toward her glove and slides.   I stand near the gloves and watch each girl execute her slide saying “Go!” in 1 to 2 second intervals as each girl begins.   This way the girls go in order and I can see each girl slide in about a half a minute.   After they complete their slide they reset and get ready to go again.   I repeat and walk the line again.   In less than 5 minutes each girl has executed 5 slides and I have been able to watch each one.     When teaching sliding I have learned the best way to get them to properly execute a slide is for them to hold a fist full of grass in each hand and as they begin to drop into their slide they throw the grass into the air above their heads and keep their hands up.