The tip is . . . Keep it short!
I made a nice 1 meter ISP cable to keep my nose out of the dust.
It never worked on one PC, so I moved it to another, and effortlessly burned 3 chips.
"It will always work now" I thought, so I left it there.
Next time I tried it - nothing.
It felt good, shortening that cable, and I knew it work, and it did.
If someone could edit the how to build the cable page, and put a note that the cable should not exceed 50cm, it might save some grief. No guarantee, but it might.