Quote Originally Posted by Foz
Even if you can't get to an enfilade position, it's helpful to get your archers as far left or right of your own melee unit & the target as possible: the more to the side they are, the less of the undershoots will fall on your soldiers (since they're less often in the line of fire). Interestingly enough, getting further toward the side also gives you a deeper look at the enemy unit, meaning not only do less under-/over-shoots hit your men, but more will actually hit the enemy.
Although arrows going to the side will more often hit your men then.
Vertical aberration seems to be more frequent though, so it's probably a good tip