On warm-to-hot days we have a bucket of ice water in the dugout, and we require every girl to have a cooling towel in their bag as part of their game gear. At the start of the game, all the girls drop their towel in the bucket to soak. Between innings, a chilled on the back of the neck (or face, or head) does wonders for cooling down.
Of course, this is in addition to staying well-hydrated.
Of course, this is in addition to staying well-hydrated.