Good artillery is a must. I often used to skip shots beyond max range into vulnerable units.

Good cavalry taking out the enemy artillery is also a sure way to speed up the battle. When their artillery is gone they usually move to attack and get eaten up by yours.

Artillery takes quite a bit of micro management though, and good supporting infantry on the flanks of it with maybe cavalry behind it if the enemy assaults it.

I hardly ever leave it out on the flanks but put it more in the middle of the line where it is better protected.