From a Denver news station piece about the germiest places.
Bathroom sinks, specifically the faucet handles, carry a lot of germs. People touch the handles before and after they have washed their hands.
Food court tables tend to be quite dirty because they are usually not washed down thoroughly.
Try to not touch escalator handrails.
Also: ATM key pads, toy stores, fitting rooms, gadget shops, make-up samples and signature pens (carry your own pen).
Wash your hands often, and keep them away from your face.