strider67 wrote:It takes practice just like anything else. But before long, you'll have it down like nobody's business. I've always been a facing the door/head on a swivel kind of guy...

That is what I was going to write.
OP, when you go out, decide on one thing you are going to look for to practice. For example; today try to pay special attention to the proximity of people to you. Count the number of people who get within your personal space. How many get without striking distance. I am not saying to go into Ninja mode

just make that your point of observation.
On another day watch people. Watch their waist line and see if you can pick out who is carrying.
My point is to train yourself to be more observant like you would anything else. It can be fun.