After warming up and stretching I like to use one of my favorite [tag]baseball improvement drills[/tag]. This drill is called the shortstop drill.
Place a player at each base and homeplate to start. No pitcher is needed. The remaining kids line up at short. Hit a ground ball to the shortstop who fields it and throws to first. The [tag]baseball[/tag] is then thrown to the second base where a catch and tag is performed. This proceeds to third base and home with the same catch and tag.
Each kid follows their throw by running to the bag they just threw it to. The shortstop runs to first, first to second, second to third, and third to home. Once the catcher receives the ball he goes back to the shortstop line.
This [tag]baseball drill[/tag] emphasizes fielding, throwing, running/conditioning, and tagging.