As one of the people who don't know how to cut the ends off correctly, how do I do that?
Step 2: Remove nail clippers from your purse.
Step 3: Use them to trim the remaining tail. One single satisfying click is sufficient to leave an end that barely protrudes, is nicely-rounded, and which lacks sharp-and-pointy features.
Alternatively: Use the China-clone of the Xuron flush cutters that your 3D printer came with, or buy some (the real ones are made in Maine). Just cut it as close as you can.
Or for higher volumes and/or better repeatability, Panduit (and others) sell installation tools that tension zip ties and automatically cut them off rather exquisitely once a predetermined tension is reached by just squeezing a handle.
Usually these are used for small wires.
Any electrical supply place will have them - search for ‘flush cutter’ and the like.
A razor (surprisingly) also works, but tends to damage other stuff easier if you slip.
You can run your skin over them all day, no issues.
I don't know that there's a correct way, really. You would probably have to take the time to file or sand the edges. Which kind of levels the playing field with the cable lacing option really in terms of time spent.
The absolute worst thing is to trim at any angle other than 90 degrees -- doing that creates a small knife.