Hey, I have a good Idea for fielding..
Just take some 80 to 100 tennis balls and put them up in the air with numbers..
You should put up a ball to a person and ask him to catch that one itself.
(eg, You should ask me to catch a ball with the number 7 on it and you should through it up. And there sould be some 50 to 100 balls at that time.)
And for bowilng, just give them a ball of heavier mass and make the people to bowl and spinners to spin. If they spin those heavier ones, they can easily put up or spin the actual cricket balls.
For batting, just put up bowling machines and don't show the batsmen the path of bowl. just keep a big thermocol and make a hole to it and make the machine's chimney over it so that the bowler will have proper sight screen and he can't predict the bowl.
See that the sight screens which they practice are made of different colors...