The main V&Vs I've never seen develop on my own generals are the natural leader line, great warrior line and killer instinct line. I've got no idea how to get any of these to increase, or even appear in the first place.

I've started to get skilled attacker quite regularly now (I only ever used to see it on autoresolved battles), and you seem to be able to acquire it without actually having to kill/capture that many of the enemy too. It seems to bear more relation to the size of the enemy force and the number of casualties you suffer as far as I can gather. I routed a Spanish army of over 1000 yesterday (mine was equal in size) only killing/capturing about 180 of them in total and taking about 100 casualties myself. My general still picked up skilled attacker for that battle, so either I got lucky or it's the final outcome that matters rather than the kills/losses ratio.

In that same turn, I had what I'd considered to be a much more successful battle where I killed/captured the vast majority of the much larger Spanish force without losing many men myself, yet my general didn't gain any V&Vs in that one. I didn't kill the enemy general there though, so maybe that was a factor?

Before I'd always assumed it depended on killing lots of men and losing very few in comparison, but that doesn't seem to be the case.