Slitherine

I understand the principle of flank and rear charge, typically delivered by surprise or simply tying up an enemy so that he can't get round in time. And, in game, I do alright with infantry and artillery units. However, I have a lot of trouble getting a handle on how to move my cavalry so as to effectively fight enemy cavalry and deliver charges in support of my infantry. Nearer the end up the battle this is easier, because things are in shambles and smoke, but usually my cavalry end up kind of futzing around at the edges of the battlefield and getting into tangled-up indecisive fights with the enemy horse.

May I ask what armies are you playing with?
Because, in my experience, it all depends on the army's list. When I play with the Spanish (XVII cent.), for example, I'm usually very cautious and almost never engage in cavalry meelé (only when It's totally necessary, and when I'm sure that I have the upper hand due to quality or quantity factors)...
However, when it comes to the Weimarian, I just let the horse units do their own battle on the wings (usually they win those) or back up the infantry to break the enemy line (once it has been mauled by shot) in surprise attacks at the center); and with the Poles (one of my favs) I just mass up the cavalry and enjoy watching glorious and unstoppable waves of Polish Hussaria trample the enemy .