Common sense and a peppergas backup!
I use common sense as others do.I think peppergas is a good thing to have handy[on my purse strap] and in boy mode on my keyring.I have used it before in boy mode and seen it's effects.However,watch the wind direction!
Not a problem... But, it could be.
Actually, it's not a dangerous world - at least not here in the USA where the crime statistics consistently show less and less crime, or, no great increase in crime, decade after decade.
Relax.
What's probably needed more than a knife or a gun is practice with verbal judo - and the willingness to "go off" on someone if you have to...
If people are going to rob you, they're going to get the drop on you and rob you as efficiently as possible. "No much, no fuss." If they put a gun on you, give them the money, the car keys, whatever... Odds are, they just want the loot and have little concern about you so long as you don't make a fuss. If they want something else... Well, it's a gun they're holding. Good luck doing much about it so long as the barrel is pointing right at you.
If they're going to beat you up, they're usually going to confront you, and/or gang up on you first. Pay attention to that sort of thing and be prepared to talk your way out, "Yep, I am a guy in a dress - you got me there. But, I try to keep the wife happy and this is what she likes..."
In any event, long story short, mind your own business, be pleasant, and use common sense to avoid trouble. If, however, you're set upon, raise hell and get in some licks as quick as you can. I've done martial arts and boxed, and spent time on the gun range. Believe me, anyone's elbows, feet, nails, etc. hurt like hell when they hit anyone else's flesh. Same for a rock upside the head, or, a phone, chair, ash tray, beer mug, etc... Just do it and do it like hell until you can't do it anymore or everyone agrees that that's enough. Point is, don't make it a "free lunch" for them either.
It's not a dangerous world unless you are totally unaware of your surroundings and your defenses.
Which, if you just read this, you no longer are.
Guns, by the way, are fine if you have one in your hand before you need it. Knives are great too, but slippery - hard to keep them from getting the damn things away from you and then back on you... And, both, unfortunately, tend to give "false security" to the bearer AND create major problems in terms of later defenses against charges of assault and/or murder.
"Premeditation" is a bitch to argue around when you habitually carry - not to mention many places you go forbid-by-law such weapons and being caught in the wrong place with such weapons is an automatic felony conviction.
Which gets back to common sense: If it's that much trouble, don't do it.