Tactics For Attrition
(written by TJJ1)

1.
Put a specialist on an enemy border and place about 15-20
L3 archers in front of him (or where you can to protect your
specialist). The AI will always send a swordsman to attack
him and before he reaches the specialist or the archers he
is dead! This tactic can be used with very very powerful enemies
to wear them down a bit before the main attack. It is also
useful on multi-enemy levels to distract one enemy while you
concentrate on another.
2.
I use this one most levels. I generally collect at least 60
and sometimes up to 150 L3 archers first (and create only
a very few swordsmen at the start).
As
a defensive tactic, stand them near a couple of towers, nothing
can get through them!
As
an offensive tactic, have a few swordsmen behind them and
get your archers to overrun an enemy tower and then send a
single swordsman to take the tower.
This way my swordsmen don't get attacked at all and they can
all be used for taking towers.