Tepid sponging is one of the best ways. Leave a small, damp, swab or sponge, soaked in tepid water under the arms and in the groin area for a little while. This helps the temperature to come down a little faster. Leave the water on the skin, but if you think the child's temperature is coming down too fast, then dry them using gentle dabbing - rubbing the skin to dry will increase the temperature again. In addition to tepid sponging some people also use cold air fans. However, I think with children, if you are not careful this can lower their temperature too fast and too low. So unless the tepid sponging doesn't work, I wouldn't use the cold air fan.