. make sure the A/C (if you have one) is not tooooooo cold.
. keep out of drafts
. my mom used to "bake the cold out of me" , give me a nice book and sit me in the sun for awhile each day..not to the point of sweating but to warm me up
. just like in winter, keep washing your hands.
. drink vit c , eat all the nice summer fruits, eat healthy