Hitting off a tee is a great drill to do alone once you have been shown the proper swing. Practicing a bad swing does more harm than good. Wiffle balls are good to use if you don't have a screen to hit into. If you don't have a wall or pitchback to throw and field against, throwing yourself pop-ups and working on your footwork can be done alone.

When practicing alone there would be some makeshift equipment you should prepare. Have a net or something that may absorb the ball coming from the batting tee. There are alot of batting tee drills you can choose from. As for fielding you can use a tennis ball or a rubber ball and practice by fielding balls bounced off the wall.

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

first how old are they and im 12 and my coach its the ball to all the places and make them throw to firs then second and third then throws them to the out field and they throw to second