Mount&Blade/Rhodoks

The Rhodoks are an unusual faction; whereas the Khergits are cavalry-focused the Rhodoks have only infantry and crossbowmen. Their spearmen have a combat advantage against cavalry but are only moderately useful against other infantry.

Against infantry
The individual Rhodok infantryman is a poor fighter; however, a large band of them in tight formation is a different story altogether. Though it may be preferable to have your crossbowmen bombard the enemy to kingdom come, if you need to engage in melee, have your Rhodok infantry advance as a large mass, where the reach of their spears can cover each others backs and deliver pointy death to their enemies.

Against cavalry
If you have a mixed array of Rhodok troops, then the best thing to do is to order your infantry ahead of your crossbowmen (this works much better on a hill), and as the cavalry approaches, they will be knocked down by the heavy fire of crossbow bolts. Meanwhile, your Rhodok infantry will have a very good chance in taking down the now unmounted riders without a problem, unless of course you are fighting a bunch of hired blades with only a handful of spearmen.

Against archers
Archers are the bane of infantry and should be dealt with quickly. If engaging archers on flat ground, have your crossbowmen (along with any fodder, such as recruits or regular spearmen - there's waste in putting a sharpshooter somewhere to die where a fresh recruit will draw fire just as well...) spread out and charge in. They will advance from the front and provide covering fire whilst drawing the barrage from the enemy archers.

Have your spearmen and sergeants pack themselves in a tight formation and move from the sides to outflank the archers either from the sides or the rear.

If engaging archers on uneven and mountainous terrain, the best thing to do is to lure them to you. Bowmen may fire faster but this also means they run out of ammunition quicker. Have your troops hide in a sheltered location and ride out to distract and draw their fire. Once their ammunition is used up they should make easy prey for your men.

Against ranged horsemen
If your army is heavy with crossbowmen, mainly trained crossbowmen and sharpshooters your best bet is to get to high ground, ranged horsemen are not quite as accurate as your ranged units and you therefore will have a good kill to death ratio, standing on top of hills also make your soldiers naturally harder to hit. Steep hills also do very well in limiting the enemy's movement speed which against your slow infantry is their biggest advantage.

If your forces consist mainly of melee infantry units your best bet is to try to station them on high ground or in a river, since most of your infantry will have access to the board shield. This makes them (except sergeants, who frequently spawn with two-handed weapons) almost impervious to frontal archery assaults, so your best bet is to wait until the enemy run out of arrows, after which they will be forced to attack your shield wall one after another, making for easy kills.

Against mixed forces
Use the set up as listed for cavalry, then ride out with heavy armor and a lance in tow once the enemy mass is in firing range of your crossbow men. Then harass their ranged units, or simply make their infantry turn around for a brief moment leaving their backs exposed to bolt fire. It works extremely well on the Nords who pack axes, and are much stronger than your infantry.

The key to this strategy is breaking up the mass of the attacking force, lessening the stress when they hit the shield/spear wall. If you find yourself chased by cavalry, run them into the shield wall, or trap them by having the chosen infantry "spread out" a few times, then "close up/charge" as you pass through (catching the cavalry in small pockets) – if you're faster than them, it's not a hard feat – then continue to distract/kill their ranged units and stragglers. Never charge the main mass directly, just lightly flank them to force them to face you and break off from the main charge.

If you charge the ground unit mass directly, you can at times get stuck or slowdown enough that they will get free shots on you and your horse. In cases of cavalry, skim the sides of them or aim for a spot which will allow for a head-on meeting with your lance, but not result in you coming to a dead stop on a horse.