In my new campaign I've got four extremely smart and strategic players. In the last session, they made short work of the enemies in what should have been a very diffcult combat situation. Although everyone had fun, I can't help feeling that I sold my monsters short by not having them be as prepared with strategy and tactics for the battle as the party was.
I posted a question to RPG Stack Exchange this week looking for help, and got lots of great advice. I also picked up Machiavelli's "The Art of War", scoured through my source material on the Mongols, and spent countless hours on Google looking for ideas. I put together the combat strategies that I've found so far and transformed them into cards for easy reference and ideas at the table.
Hopefully someone else might find them of use in their own games. I'll continue to update the deck as I discover or create new unit tactics.
You can download and print the Mixed Unit Tactics Cards now.