I think the best thing you can do is exploit the terrain. Look for high ground or possible chokepoints. Never use your cav and guard units to early, they are gamechangers and should be used in the late game.

Protect your artillery with cav or infantry. Try to elimenate their best infantry first.

And most important of all...FLANK. Dont mindlessly charge with your cav. Just wait for the right moment. The patient ones always win.