Here is a useful article which made me think:
In the kits I have built, I did not realize I should plan for this, or at least not consciously. On the other hand, apparently I “naturally” followed this to some degree. In my small kits, it applies in the most limited fashion. About the only thing in a small kit which needs to have any attention paid to it is the flashlight, and only where practical. As the kits get bigger (and the container more complex), this becomes more important. And practical.
In my medium (shoulder bag) kit, I have a tourniquet, Quick Clot, Israeli bandage, FP3 mask and flashlight in external pouches/pockets. Attached to D Rings on top are a small strobe light and a compass. Open the top, and there is a red LED light hanging from a zipper on the top flap. All the small items are in the mesh pocket and elastic loops of the top flap. Everything else pretty much is crammed in where it will fit.
The bigger the kit, the harder it will be to find what you need immediately, so the more important intelligent packing becomes. As usual, keep the “rule of threes” in mind.
Three seconds can kill you if someone or something is attacking you. When I am carrying any kit, any personal protection is not in the kit, it is on me in a holster or sheath. I don’t pack large knives or firearms in any kit, not only because they tend to be bulkier than other gear, but are more expensive and harder to replace and then there are liability and safety issues. I “strap them on” when picking up the kit. Having ammo, parts, accessories and tools for them in the kit is not a problem.
Three minutes without air or with extreme bleeding can be fatal, so any filtration mask and bleeding control supplies should be immediately to hand. And, darkness can hide all kinds of dangers, so a light should also be readily available.
Other than these things, handle small items carefully, so they can be relatively easily found, and are unlikely to fall out of the pack when pulling something else out.