I've come back from a long (and I mean long) hiatus from the game, and I get the feeling that, due to how much i used to play it, some of my strategies might actually work.

one strategy I figured out was to avoid battles wherever possible. This is because the battle only ends when all units from either side have completely left the screen, which if you only rout the enemy can take longer than is wholly necessary. whilst you could try to flank the enemy, due to how long it takes to command troops, it's not always an effective solution. therefore, avoiding battles wherever possible, whilst still fielding a large army, is a good idea.

another strategy I found was to kill your rivals by duel, rather than stealth. This is effective for 2 reasons. reason 1 - it's much quicker than fighting through all of their retainers (on higher difficulties at least, i only play on Katana and No Dachi). reason 2 - the margin for error is a lot wider, because you can afford to take a few hits.

as i discover more, I might post them here, if anyone's interested.