Have you found any good strategies that keep your absenteeism rates lower?

We introduced a school wide award that is awarded to the classroom in each grade level with the highest attendance rate each month. When our individual classes have attendance above 95% on a daily basis, we get a postcard with our mascot on it to display outside our classroom door (with the date earned). When our classroom earns 10 of them, we get a visit from the Woot-Woot wagon and each student gets to pick a treat!