On the postcards ( index cards) I'm using, it has one side with lines and one side that is blank. On the blank side I put my return address on the left hand corner and the Disney Dreams Giveaway address in the middle (with a stamp of course). The personal info going on the lined side (with my very best handwriting) on the back.
I am using the pre-stamped ones from the post office, they are blank except for the stamp. I put the mailing address on the front with the stanp and my information on the back.