Way back in my career as a NASA engineer, I spent most of my time training. You see, I wasn't a design engineer - I was an operations engineer - we got to take all the cool stuff that the rest of the aerospace industry built, and make them fly. Much of that work was operating and troubleshooting systems, and part of the job was learning how to fix things "on the fly" so to speak - including things that were never designed to be fixed in flight. Did you ever see the scene in the movie Apollo 13, when they had to make square CO2 absorber cartridges fit round holes? That successful effort lead to an entire discipline in the Space Shuttle program, and we all got a chance to learn the procedures for re-wiring, troubleshooting, and replacing avionics boxes in flight.
One of the courses I had to take was a technician's course in making good wiring connections - crimps, joints, splices - all that good stuff. I spent a lot of time at a work bench, having my work evaluated, and that sure paid off when I was building my own airplanes. I enjoy making nice tight wiring bundles with all of the ends fanning perfectly into the connectors. It's a small thing, and always hidden behind panels - but I like to be neat.
The neat thing is - you don't need to go to work for NASA to learn what I did - NASA has an on-line reference manual, with pictures, that shows you how to cut, strip, and crimp wires to aerospace standards. If you are getting ready to wire your airplane, its worth your time to take a look and learn what good wiring technique looks like. And don't worry - its not actually rocket science - anyone can do it, with just a little patience!
Have a look at The Inspector's Pictorial Reference.