Slip the money belt on under your clothes (placing the belt over an undershirt may be the most comfortable option) before leaving your hotel room, and make sure to put any cash needed for planned activities in your pocket or wallet.
Place all other cash, credit cards, passport, traveler's checks, and travel documents such as plane or train tickets in the pouch pockets of the money belt.
Head to a restroom or other private place if you need to take something out of the money belt unexpectedly. Otherwise, grabbing your money belt in public tells the world where you store your valuables.