Cool off often. If you are overheating, place a cool, wet towel around your neck, splash water on your face, grab a cool drink, or get a breath of fresh air. All of these things will help to regulate your body temperature a bit faster, which will slow down the sweat production. Anything that will cool your body temperature down will slow down the waterworks. If you had a sweaty day, take a cool shower and change your clothes.
Nothing feels better than a fresh outfit after a hot and sticky day.
Rotate your footwear. This gives your shoes a chance to dry out. Sandals are especially great in hot weather, because they allow air to circulate around your feet and dry the sweat. If it isn't sandal weather, try foot powder or absorbent insoles. Make sure you replace them regularly, these can create stink after awhile, instead of helping to eliminate it.