Carry your essentials in a med size waist pack made by, northface, timbuktu, or a tactical hippack. Wear you shirt partially over the pack. When walking, touch it every so often if it is behind you, as you are aware of it. When on public trans, if you can sit leave it behind you, you can nonchalauntly sit back on it, if you have to stand turn it around to the front,
Dont carry laptop if you can help it, nor expensive equipment unless you can creatively make it blend. Copy what other people do, blend in as much as possible. Its all about being familiar with evrything around you while being casual.
If you stand out, you will be studied, if you blend, have confidence, talk with friends (without running your mouth and giving all your Bio away, relevant conversation) act casual, you will be noticed because new yorkers notice everything but will be tuned out.
NEVER take cash out radomly, always know how much you have where it is and how it is stored. Store it in a fold in your front pocket, try not to carry a "lump" in your back pocket.
When you do take cash out, try to have what you need so you don't fumble with a wad.
PAY ATTENTION to placing your pin number, take a look at your environment, if someone is giving you the creeps, stay to yourself.
What I mean is, New yorkers have unwritten rules about personal space, when that personal space is being invaded (you need to become defensive, but be tactful). When there is no space like rush hour on sub way, you have to comprimise, the rules change a little, NEVER do anything unwittingly when crammed into a space, elevator, subway, a line, a crowd, pick pockets know how to barely rub to pick you.
WARNING, be aware of any unstable characters who seem to be on drugs. You may notice them as they behave a little differently that the norm, a lot of addicts are careless as they have become so familiar with the city that they don't care (this is not a rule for all however).
DO NOT BUMP INTO THESE PEOPLE. I have personally seen uncovered hypodermic needles sticking out of bags and you don't know where its been.
For that matter becarefull of any package or bag because you don't know what is in it,
Dont freak, just think of these things remember NEVER DO ANYTHING UNWITTINGLY.
When on subways and the like watch for alarming patterns in behavoir, keep an eye on peoples hands that are near you,
If you witness something criminal, do not stop, do not watch, keep walking or leave the area without drawing attention, they key here is MIND YOUR OWN BUSINESS. If someone's life is in danger and not many people are around YELL "FIRE". If you are in a subway get the train conductor found in a small box in the corner of the car. There are transit police that can handle that.
If you are thinking of carring a knife or gun for insurance, don't, there are stiff laws that will land you in rikers for that. The best way to deal with potential danger is creativity and common sense.
If someone askes you if you want drugs on the street, say no thank you once politely and IGNORE any more interaction and keep walking, if someone says "trees" or "smoke" repeatedly they are selling weed and are liable to not only put you in danger but get you arrested for drug charges NYPD can use this method as bait or you could be caught as a buyer, regardless NYPD doesn't care if you were just talking because they assume you are as street smart as the dealer, don't even associate with them.
Gypsy cabs, in the outskirts of manhattan and outlying bouroghs (bronx, brooklyn, queens) people use their own cars to pickup fares to make money, do not get in the car, take the same approach as a drug pusher, this is obvoius, they could abduct you or even if they have good intentions, can put you in danger. Some times they pickup a second set of strangers to make money while you are in the car, they may be approached at a corner or involved in some other danger.
Do not stay still in the subway station entrance, people will be looking for used metrocards or ask you for money or a metocard, if you are being botherd tell the token booth clerk. Point is BUY YOUR FARE AND MOVE.
GENERALY you need to have a place to go and go there, do not find your way as you go, know where you are and where you are going and how you will get there.
While walking, your eyes should be moving at all times, cabs do not stop and will hit you, don't bother with crosswalks no one believes they exist! When people find and opening in traffic walk among them. Keep your eyes on what street signs are on each corner, look for the green set of lighted balls for the subway, know your route and any options for travel while walking, you have to process new info as you move.
Some of these things listed may never manifest at all, but you must be aware of them. This ia not a matter of paranoia, THIS IS A LEVEL OF AWARENESS that you must act out.
When all else fails or don't know what to do USE COMMON SENSE USE COMMON SENSE USE COMMON SENSE.
Dont look like a tourist.