I find 1 militia sergeants/chiv sergeants + one reasonable missile unit makes for quite ample garrisons. Dunno about when you are at 60% though, haven't been playing enough to finish a 1.1 campaign yet.

I keep on seeing people talking about training up their troops in battle.
Almost all the valour increases I manage to make are via generals going up in stars.

Cavalry definitely manages to go up. 10+ often enough with general bonus.
The better foot/missiles that have been in battle lots I will manage to get up maybe to 2/3 if you take them out of the army so you can see without the general bonus.
But most of my troops never get past about 1-2 without the general bonuses.

I guess it might just be my fairly conservative style.
I tend to make sure I will definitely win, or otherwise have just so many people that the other side will not attack or will run away without fighting if its me attacking.
Most of the time I'm not attacking, so my missile units get most of the kills and my cav get most of the captures.

More recently, I have been being a bit less careful, throwing armies around without much planning etc and I am finding that I am getting more battles where units go up 2 valour and several/most of the rest go up 1.
The flip side is that I am also taking much higher attrition, so by the time the depleted units are restored to full, most of the valour gains are averaged out. Sometimes I am even completely losing high valour units because I send them off unsupported and they get sandwiched before reinforcements can get there.