What type of drills? Softball drills or fitness drills? If you want fitness drills www.youthfitnessmag.com has some nice training tips and what not.

Use a circuit of stations. Teach the kids various series of circuits--one for PB, one for fielding and one for fitness. Research activities for stations that are challenging. You might keep a clipboard at each station with a roster to chart the result for that day at that station. Girls can compete against themselves, as micro teams, and for the stud of the station. Keep the numbers small for each group to maximize hands on and to limit standing around. Encourage cheering.

If you have assistants, set them up at stations as needed for pitching, serving grounders, or set up the teams so that as they rotate, one team takes a turn to facilitate the stations.

Start each practice with a fun warm up game--preferably exactly when practice starts to encourage them to be on time. Eliminates the need to punish because they miss out.

End each practice with a team challenge--either fitness or a skill that can be judged easily with a large group. Hell drills can be good to finish on from time to time. Make up a fitness or skill challenge that requires everyone to beat a time set by the team previously, or perform a skill perfectly in succession by each team member. I've heard these called "The Pit" or other not-so-nice things. They sometimes lead kids to tears and cheers, and can really build unity and support. They also need to process how to support a kid that gives up.

Avoid drilling when possible, use small groups to minimize standing around, incorporate a challenge, and keep it fun.

A couple of fun drills I use at the end of my practices are the relay drill, set up teams of three one in the outfield one as cut off and one set up on the base line. Build the three bat teepee with a helmet on top. Then hit or throw the ball to the outfielder they need to throw the ball ot the cut off then the cut off throws to the infielder who then tries to hit the bats or helmet. I also set up buckets next to them. They get 2 points for hitting the bats 3 points for the helmets and 1 point for the bucket. The players rotate after each throw. Rotate through each team until you have gone around to each player at least once.
The second drill is a conditioning drill they all love to do. 4 equal teams one on each base and plate. make the teams up of equal speed. Each team has one softball each. Then they race around the bases touching each base and handing the softball off to the next runner on there team, just like a realay race. Winning team get to run the stations at the next practice.

Stations can consist of soft toss batting, hot patato, agility drill, over the sholder drill and throwing the bat drill.

I also like to get the players to think while doing the drill's. Ask questions the right answers get 2 minutes off of a practice (my girls like to bank the minutes to get a night off) Questions can be like what is the infield fly rule? what do the runner do if there are 2 strikes3 balls and 2 outs? what does it mean when a the infield ump put there arm straight out?
They can also earn 5 minuts off if they can come up with a rule or a question that i can't answer.
This gets them to think about the mental part of the game and you to under stand the rules.

Make sure that you're addressing all skills in softball in preparing drills. You can have combination drills like base running and fielding. Batting and Pitching...Batting and fielding....you can have integrations of games with your infield games....practice game situations as well

http://www.softballperformance.com/softball-drills/