I avoid bathing for several months before leaving so that pickpockets don't come close. Of course, no one else does either, which is GREAT in a crowd!

Eating lots of beans and cabbage helps too.

Can you imagine how PEACEFUL it is being in the Sistine Chapel, on a busy, hot, day in the summer, and being ALL ALONE! Just awesome.

--Marv

But seriously, I do wear a hidden wallet (suspended inside my pants) for valuables that cannot be left behind in the hotel safe.

--Marv

It looks odd when I read this, but good posture and liberal eye contact helps.
A person doen't want to "stare down" the wrong male, but make certain everyone understands that you know where they are.
I do carry two wallets. One is a decoy with nothing of value and somebody else's business cards inside. The other wallet is well-secured.

Back in WA State, I carried a stun gun, but only to protect our English cocker after she was almost killed by a "nice" Rottweiler. Here in Europe, where I have been a crime victim (as noted on a older post), I don't carry anything in particular. Most things that would be legal to carry in the U.S. aren't in Europe. However, I do wear coats with zipped or buttoned inside pockets and keep my wallet there and then my coat buttoned up. I have on order a new Delvaux purse that has an anti-pickpocket design, but that won't do me much good if someone decides to take the whole purse...
Like Scarlett, I find a large husband makes a good theft deterrent. But not always--on a crowded Paris metro, a gang of thieves targeted my husband, not me. They *almost* got his wallet, but not quite and quickly left our metro car.

A home exchanger, I packed a lunch, did a long Sunday walk and late in the afternoon, I went into a Casino. A degenerate gambler, I had won about 1700 dollars. It was late in the night--around three a.m., beautiful night, and since I had been sitting for hours, I decided to walk to the trolly stop which I had used often. As I approached it, I noticed two men standing away from the kiosk, and I got a bit anxious.
Here I was, a 75 year old geezer, with a lot of money in my pocket. I 'knew' I'd be mugged.

I reached into my bag and took out a hard-boiled egg left over from my walk. I cracked it, and proceeded to peel it slowly, tossing the peels on the track, and ate it.
I wanted to look like a very poor man who couldn't afford much and had to eat an egg.
It worked. The two men did not mug me and I got the feeling if I asked they would have given me some money.

Don't rely on a "large husband" to keep you safe from pickpockets. Although my own six foot tall husband (or I)have never been pickpocked, a close friend of mine who is 6'3", looks like a football player, and is a native French speaker had his wallet stolen on the Paris metro. He still hasn't forgiven me for responding to this news by saying "What the hell was your wallet doing in your pocket on the metro!"

I always use an under the clothes security belt for passport and extra credit card, ATM and cash. I carry in my purse only one credit card and a small amount of cash. And most of the time I carry that in a tiny pouch in my front pocket and have a string attached to the belt loop. That only works when wearing jeans/slacks so when I'm wearing a skirt (summer time) it goes in my backpack style purse along with camera, etc. But I have a tiny combo luggage lock holding the two zippers closed. This might all sound like a lot of trouble but it really isn't and I like the feeling of security. I am still aware of my surroundings as others have said, but I don't think about it all the time. I know I'm often distracted by what I'm looking at. After all, that's the reason I'm there. So I like to know that if I am the target of an attempted pickpocket they won't be able to get much.