If you have help split your team in half, stand them in a line with you and your help rolling grounders to them one at a time so that they can learn that all of them will have a chance at fielding the ball they just need to wait their turn like the drill.

The drill we do is we put a chalk line in the middle between 1st and 2nd base
and the middle of 2nd and 3rd base.(3 foot vertical line.) so we "split" each base into a "section"
We let the kids know that if the ball is not in there "section". they are to go to there base. we do this for about 5 to 7 practices.. makeing sure each kid has a turn at ALL the bases..Also we let the infield know that if the ball goes into the outfield. there are to NOT chase it. but go to there base.
REPATITION is the best, they will not pick it up after 1 or 2 practices.. you need to do it for 5 to 7 practices.. after that you dont chalk the line...by then they have a understanding of what there job is at each base.
For a pitcher we make a circle around him (12 foot diamater) let him know that if it is not in his section to stay at the mound. Out field also knows that they are not to go into the "dirt". for the ball They stay on the grass..
Dont know if this helps it works for us. Please let me know If you have any questions please let me know

Teach them to run to first before you let them hit off the tee...

have two line one at short one at second. Tell them if the ball is rolled to them they field, if not they cover 2nd. The child fielding the ball throws or underhand flips to the child covering second. Prior to ending this drill make it an elimination contest (make an error you are out) the winner gets to pick his line-up spot in the next game.

Make the players stay in there postions. Say if it is hit to the 1B the 1st baseman go to get it