To protect oneself from pickpocketing while travelling, one must TLC - Think Like a Criminal. An appealing target for a thief looks like they cannot react quickly or do anything to stop the theft. They are looking for tourists that have:
both hands tied up with bags or pulling suitcases
something tucked under their arm
distracted by their phone, camera or eating
a crutch or aircast
set a bag down and turned away for a moment
an exhausted appearance
Distraction tactics such as inappropriate public displays, spilling something, or bumping into someone also tricks used by pickpockets. Tourists can also be disarmed by friendly strangers who sit down and befriend them at length, only to suddenly jump up and run away 30 minutes later with every bag.
Pickpocketing can happen anywhere and can have a devastating effect on a trip. Some simple tips to reduce the risk of theft:
Disguise expensive equipment that you must carry. In the photo above, black removable tape hides the bells and whistles of this 3D video camera. If you are carrying photo equipment, avoid using a camera bag and use a generic bag instead.
Avoid wearing expensive jewelry, watches, purses, etc. Instead, get a cheap one to travel with. Think function over fashion when avoiding pickpockets.
Don't check your valuables when you read a sign that says "beware of pickpockets." This is a very effective way for thieves to learn where the you put your most important items. In fact, they put these signs up where it is easy for them to survey a crowd.
Don't sling bags behind your seat or underneath you when you sit - keep them in your lap.
Try to keep both hands free.