I usually don't choose any angle of attack. My main setup is to have archers and calvary. The calvary is to keep their calvary off my archers and to thin the enemy out a bit. The archers will pick off (quite effectivly I might add) the straglers and the normal infantry that rush the archers or calvary. My armies almost never have any normal footroops (except for the Pirates mod because horses are hard to come by).
There are times when you need to flank the enemy. I flank when the large portion of the enemy is archers, I send my archers up against them to distract and I tell my cavalry to follow me and we flank them behind the hills and rush up on them, but you WILL NEED a shield for this or else you won't get within 50 feet of the archers. Then the overwhelming numbers of calvary will break into them and prevent them from firing, and then you slice them up. Another flank move I do is by myself. If the enemy consists of many types of troops I will order my men to charge and I will flank in behind their archers and lance them to prevent them from picking off my horsemen, then I work my way to the enemy calvary and I lance them, this also works with the bow and arrow, but don't engage the enemy archers at close range with a bow, they will get you every time.
If you get the battlesizer thing, you won't worry to much about flanking, the enemy forces and your forces balance out and you must use your skills to tip the the battle in your favor. Perhaps if they had bigger battle maps, it might give you enough time to coordinate an attack and place your soldiers. O yeah one last hint, if you are facing overwhelming odds or large numbers of calvary and you have mostly infantry, try to find a tall hill and tell your men to hold the position, the enemy will have to basically walk up, making them perfect targets, another good spot is a river, you can put your infantry in it to slow down the calvary which reduces their effectiveness, and then put your archers on the opposite bank to fire on the waterlogged horses while you take your calvary and flank from the sides.