Seeing as we are talking about tips to prevent fraying... Here's my tip, two tips actually).
When replacing the gear cable the inner wire has a tendency to fray, which is why you are supposed to fit a soft metal cap on the end. But that cap can come off and fraying commences.
First tip is to fix the fray by fastening a small zip tie around the wire and unwinding it slowly up the frayed wire. The zip tie puts all the frayed wires back in place.
Second tip is to put a drop of superglue onto the end of the wire when new (or before your remove the zip tie from the last bit of frayed wire). The liquid superglue runs down the spiral wires and then sets them into a solid mass.

Be careful not to put too much on or you will end up with a zip tie glued to your gear cable!
I still fit the soft metal cap, even when I've glued it, because even if not frayed you can still spike yourself on it.