[Ironhawk]

People will of course take issue with what I lay out below but the OP asked for basic (general) layouts so here is my default...

Basic Troop Layout:
Most forward block - heavy inf, high prot or at least troops with big shields
Flanking blocks (slightly back/to the side of the HI) - light inf or specialty troops
Archers - Fairly close up behind your infantry, modifying for weapon range
Cavalary - off to the far sides so they can flank if they make thier rolls

Army Placement:
If you have strong missle/magic firepower, place your entire army further back on the field and set your men to Hold and Attack. This allows your archers/mages to fire more times while they enemy approaches.
If you have weaker firepower, then place your men as far forward as possible with orders to Attack. This will reduce the amount of time the enemy gets frienly-fire free shots at your men.

Squad Size:
Units with lower morale need to be in larger squads to reinforce their communal morale. Units with high morale can be used in smaller squads. My rule of thumb is that a squad is 30ish men, a small squad is 15-20, and a large squad is 40+. You can also pepper low morale squads with high morale troops to bolster them up.

Assorted Notes:
-Attack rear is a finicky order, as you have found. Orders like Attack Archers/Cavalry/Largest are more effective. If you know that your enemy will place units of one of those types in his backfield, use the associated order to attack them.
-If you have a unit with an optional missle attack (like javelins) that you want them to use, you must leave them on default orders or Fire. If you give them an Attack order they will not fire as they approach. Very handy for light infantry.