There are a lot of good pointers here -- thanks to all who've posted them. Most of this advice pertains to what we do when out and about in the world... I have another set of concerns, though, and I'd appreciate any input on my particular situation. I work alone, in a small storefront in a decent, mostly residential but urban neighborhood. There's no cash on the premises (would that there were more, she said laughingly...), and nothing of value visible from the street. I keep the door locked if I'm there late, but that's not practical during business hours. My dog comes to work with me, and she's my main deterrent, I guess: she's a bit of a wuss in a lot of ways, but she weighs 65# or so, she's quite territorial, and she seems to have good instincts about people: she's normally very friendly with my customers, but the few times someone I've had a bad feeling about has come to the door, she's either barked, or stood off and kept a close eye on them.
Anyone with a similar work situation? How do you discourage undesirable folks? What else should I be doing?