I think garrisons (and AI battles) go by numbers, not quality, so just fill them up with recruits. At half wages you can store a lot of recruits in a castle.
I survived my early warring by mercing out. The pay was not near enough to cover expenses, but I could attack small sea raider parties and bandits and such with a place to run to if I ran into a party that was too too big. Also I could join the lord's battles and take some of the loot as well as improving relations. Of course, once peace was made, morale dropped quickly (I didn't want to lose the men I invested time in training) and I just about went broke until I got the 'start a war' quest.
By then I was fairly strong (50 or so men), and the new marshal was pretty inactive (kept chasing sieges, only to show up too late or to have nothing happen), so I broke my contract (my relations were good enough that I didn't get in too much trouble) and went to go help a claimant. By then I had an almost entirely mounted group, so I could do hit and run tactics until I was big enough to have real battles and sieges etc.
So that's what I would do if I hadn't doneit already.
I survived my early warring by mercing out. The pay was not near enough to cover expenses, but I could attack small sea raider parties and bandits and such with a place to run to if I ran into a party that was too too big. Also I could join the lord's battles and take some of the loot as well as improving relations. Of course, once peace was made, morale dropped quickly (I didn't want to lose the men I invested time in training) and I just about went broke until I got the 'start a war' quest.
By then I was fairly strong (50 or so men), and the new marshal was pretty inactive (kept chasing sieges, only to show up too late or to have nothing happen), so I broke my contract (my relations were good enough that I didn't get in too much trouble) and went to go help a claimant. By then I had an almost entirely mounted group, so I could do hit and run tactics until I was big enough to have real battles and sieges etc.
So that's what I would do if I hadn't doneit already.