Here are my thoughts;
Back in the day, I was a pizza guy too. My buddies family owned the place, and I delivered for them to make some extra money one weekend. It turned out to be pretty easy (or so I thought), and ended up signing on for longer. It paid for my first truck and I'll still do it on a very rare occasion if my buddy needs help and I got the time. In a very similar part time job I also had, I delivered prescriptions for a local pharmacy. I eventually moved on to work for a Rx distributor, delivering the drugs to the pharmacy. I still do this on a rare occasion to. I did the latter in rough areas, like D.C., Cleveland, Baltimore to name a few. All that led to fairly decent paying high risk high value courier jobs that I still do to this day. ( have you ever delivered methadone to the methadone clinic?... it gets a little sketchy sometimes) There have been several attempts to rob me, none have been successful to date.
Anyway, here is what I learned.
DO NOT carry an extra bag, like a fanny pack or murse. If you get jacked, the first thing they are going to take is any bags. Chances are, they will have a jump on you, so thats no good. Do nothing that makes you stand out or draw attention to your goods. In the case of the pizza man, everyone knows who you are, but don't draw attention to the money. Carry as little as possible. Each time you go back to the shop, make a drop.
I've found that carrying in a 5 o clock position is best for deliveries. Carry the bulk of your items in your left side (assuming thats your offside) and do everything possible to leave the right hand free.
Get a good holster and belt combo, this will help tons. Crossbreed, High Noon, Comp tac are the brands I use, but there are others as well. See our sponsor board.
And for the love of God, carry a dang flashlight! They make mighty small and powerful ones these days that are very inexpensive.
Practice drawing in and even shooting from your vehicle if possible. Most confrontations take place in or at least near your car.
For the other items you already carry;
Don't carry your knife in your right pocket. Although most people do, thats bad juju. Switch it to your left back pocket.
Keys; put them on one of those climber clippy things, or get a key keeper and have that on your belt. Just have your car keys with you. I made another set just for delivering. That way, I always had my normal key set at the shop in case they got lost, stolen or whatever. If they do get stolen, you gave them your car key and not your house key.
The rest can stay the same... but what did I just do? Your right front pocket is now open and an option to carry there now too.