Keep your belongings with you at all times.
At a restaurant, do not let bags hang from your chair with your back to them or rest your wallet on the table while you eat. Keep your bag on your lap or on a second chair fully visible to you.
On the street, avoid showing your wallet or other valuable belongings. Put away your camera or laptop when you are not using them.
Walk on well-lit streets.
Favor streets where you see good lighting and other passersby, even if it means walking a few extra blocks to reach your destination. After 10pm, always take a cab.