There are many things the player can do other than commanding their army to achieve victory. It is not uncommon for a battle to be won simply because the player can kill so many units. When fighting enemies, there are things to watch out for - a lot of things - and there are things that you can do in almost any situation that can result in a better battle outcome.
You must keep yourself alive during fights. Besides the obvious of wearing really good armor, there are many things you can do to prevent yourself from being defeated.
This one is obvious, blocking prevents a melee weapon (or projectile if you're using a shield) from hitting you. A shield is best for blocking, due to its omni-directional block and its ability to block projectiles, but it shatters after enough hits and enemy archers can sometimes shoot above or below your shield (depending on its size) and hit you, and some shields are vulnerable to penetration from weapons such as crossbows. Blocking is a good way for you to prevent being "Lancesassinated" by enemy cavalry, due to the fact that their lance would bounce harmlessly off your shield or be blocked by your melee weapon. Note that if on a horse, blocking does not prevent enemies from hitting your horse. A good tactic to use is to keep a shield in your inventory at all times. Even if you aren't using a one-handed sword or polearm to use the shield, the shield protects your back.
Enemies with projectiles will always aim perfectly at you. If you are moving at least somewhat perpendicular to them, they will miss every shot. It can be useful for you and your army to circle Nord armies until they waste all of their Javelins and Throwing Axes. It should be noted that, in With Fire & Sword, bullets fly too fast to effectively dodge at longer ranges, but they lack the accuracy for this to be a great problem. Your horse is likely to be hit several times, even if you dodge perfectly.
Jumping can get you out of a lot of sticky situations - especially when you are on a horse. If you see that you are about to ram into another horse, or even a smaller rock, you can jump over most of them to avoid stopping. This will prevent you from stopping which leaves you vulnerable to lances, ambushes and projectiles.
Longer reach weapons prevent enemies from being able to hit you while you ride by on your horse. This is why a lance can be considered the best type of weapon. Ranged Weapons serve the same purpose. Horse archery can be one of the best strategies since, if done properly, you will almost never die.
When on foot, cover (rocks, trees, a horse, etc.) can save your life. You won't be able to get hit by projectiles and horsemen won't be able to hit you very easily if at all. On top of that, due to the 3rd-person view, you can still see around a tree or over a rock. When enemies approach, you can take them out one-by-one, maximizing your damage if you are to die there.
- Backing Up
When fighting larger groups of enemies on foot, you can walk backwards while you swing your weapon to prevent the enemies from surrounding you. If you are surrounded, you are very likely to die.
- Boat Battle
Since horsemen (including yourself) can only really attack at their sides (unless you use a spear or lance), you can beat other horsemen by slowing down and turning so that they can't hit you. You can then kill them and/or their horse. It is similar to boats which can only shoot sideways. In order for them to both shoot, they must path parallel to one another. Enemy AI is not smart enough to do this so you can beat most horsemen using this tactic.
When you are fighting enemies that have longer weapons (2-handed axe or voulge etc.), you may notice that it is harder to get in to attack them without getting hit. If you charge towards them and then slow down and turn your horse away, they will swing their weapon and miss. During this time, you can turn back, speed up again, and hit them with your weapon. This is particularly useful against Vaegir Guards and Nord Huscarls since they are likely to wield 2-handed axes.
- Block a Couched Lance
When your shield is broken and all you have with you is a melee weapon, and you see a knight about to lance your face, you can chamber block even a couched lance! Normally, couched lances are completely unblockable without a shield, but sometimes you can chamber block a lance. The timing is quite hard, but you'll get the hang of the timing. To do this, when you're just about to get lanced, start a thrust attack about 0.8 seconds before you think the lance will hit you. If you do this right, you'll hear the sound of metal clanking, and you're alive! If you're too early, the chamber block will not block correctly, and you're dead. If you're too late, you'll get lanced before you get the opportunity to even press the left mouse button to chamber block! Remember that it depends on the horse's speed. A saddle horse trying to lance you will have a completely different timing than say, a courser. The mistake beginners to chamber blocking do most is doing it too early, because they think if they hold the attack direction they'll be immune to that direction, and end up getting skewered. You chamber block by starting the attack when the attack should hit you.
Killing enemies effectively can cause a battle to end massively in your favor since you and your army will not have to fight against them as long.
- Divide and Conquer
When the battle starts, and all the soldiers are scattered in a giant battle, it is good to pick off all the stragglers. Archers and crossbowmen will be scattered and will be aiming at various targets. Protect your buddies by killing them. After the archers have been taken care of, you can focus your attention on groups of foot soldiers. They will be busy fighting or running after some of your troops and you can come from behind, trample through them, and kill a couple as you go through. Generally you can ignore cavalry until later since they are harder to kill and they will just chase you around while missing attacks. If cavalry hit your archers, you should defend them, and if you get the opportunity, take one out that is focused on an allied soldier.
- Target Lords
Defeating an enemy lord is very gratifying and also awards lots of experience. It also causes their army to lose morale so they will run away more easily. Knocking out a lord is usually not too hard because they usually don't have a good horse, and once on foot, you can defeat them easily with one ride-by.
Lords are typically representative of the heaviest enemy troops and can inflict significant casualties against light troops or preoccupy your heavier troops. Eliminating enemy lords greatly improves the effectiveness of your troops. An excellent opportunity for this is looking for the one oddly-equipped soldier who lags behind and to the left of the main enemy line before they charge. A deft horseman can get around the enemy and target him.
It is advised that you get a Charger if you intend on using this strategy. It is very easy to ride by and kill units that are not paying attention to you since their Shields will be pointed the wrong way, projectiles won't be fired at you, and then enemy won't try to hit you. But when an enemy is facing you, they are very likely to just block your attack. After repeatedly blocked attacks, your army will start to dwindle and your horse or you may suffer some damage. If you ram an enemy just before swinging your weapon, you can still hit them and they will not be able to block. This strategy is bad against spear men and doesn't work if you are using a lance or a spear.
- Slow Horse
When fighting an enemy with a polearm, your horse will take a lot of damage and will be stopped if you charge at them. If you can't get them while they are looking the wrong way, you should slow down your horse so that their stab deals little damage and doesn't stop your horse. You can then proceed to attack them.
- Hack and Slash
When fighting on foot against a large group of enemies, attacking alternately right and left causes enemies to block incorrectly causing almost all of your attacks to hit. Since you are swinging right and left, you don't have to aim. This is best with a two-handed weapon or polearm that swings similarly.
- Leg Shot
If your enemies like their shield (i.e. keep it up at all times), you can shoot at their legs and usually it will hit them. This doesn't work against Rhodok soldiers or Nord soldiers (and various other shield-using higher tier units). Note that this can also be an important tactic in Tournaments when you are put on foot with a bow and your enemy has a melee weapon and shield.
- Stop Blocking!
When fighting with a ranged weapon, you may find that enemies just block your attacks all the time. If you wait until they are pretty close, they will raise their weapon to attack. At this time, you can shoot them anywhere you wish. This works well if you are down to just footmen while you are playing as a horse archer. It's also useful if the melee fight is just about to start and you are on foot. You can get one last shot off before pulling out your melee weapon.
- Wall Kick
In sieges, you can kick (kick by pressing E) enemies off the walls when you're attacking. Not so much when you're defending, but it is still possible. Falling does a lot of damage, and if it does not kill outright, you'll have weakened the enemy by an average of 15 hitpoints.
There are many things that you can do in a battle that are handy but not obvious.
- Trade your Horse
Give one of your companions the horse you want to ride (e.g. Champion Courser) and put them in their own unit group. Tell them to dismount and take their horse and then tell them to mount and they'll grab yours. Since you are not on your horse anymore, if it dies, it can't get crippled or die. And since you are on someone else's horse, if it dies, it doesn't matter. This way you can ride your Champion Courser without the fear of it getting killed or crippled.
- Horse Thief
At the beginning of the game to mid-game, you probably don't have a charger, war horse, or courser due to the fact that you're spending money on troops, production enterprises, or better armor/weapons. If you have enough riding skill and you kill an enemy on a horse, you can get on his horse. Not being on your own horse, your horse can not be crippled or die. This strategy also works in tournaments, where you may not always spawn on top of a horse, but your opponents (or allies) will.
- The Jump Stab
If you are armed with a spear and nothing else, you may notice that you can't attack when the enemy gets in your face. When you jump, you gain a small speed boost but you also stop momentarily when you hit the ground. If you jump away from your opponent and ready your stab, you can actually hit them even though they were in your face.
- Rock Climbing
If your opponents have no ranged attacks or have run out of ammo, you can stand on a rock by jumping on to it. As long as it is big enough, enemies can't hit you while you stand on it and you can take them out with a bow or long weapon.
- Horse Wall
When fighting horsemen (this is typically best if you are on foot), if you leave their horses alive, they will block their reinforcements from charging properly and stray horses may stop their riders leaving them vulnerable to ranged attacks.
- Hold your Fire
Sometimes an enemy lord will have their army stand still and fire projectiles at the approaching army. When this happens, the enemy archers will generally be in front of their soldiers. If the enemies are focused on your troops rather than you, you can trample your way through the archer line swinging away as you go. If you do it properly, you will kill a few enemies and cause the rest to fall down temporarily. This will stop them from firing their weapons and damage their morale heavily.
- Wrecking Ball
When at very low health, it is difficult to remain useful in the fight. If you have a shield and are riding a Charger or another kind of tankier horse, you can just ram enemies instead of attacking. If you have two shields, this is even more effective. Just ride around with your shield up and ram into enemies at high speed with your horse. It will deal damage and hurt enemy morale while knocking them down and preventing them from attacking your troops.
When holding an overhead when the AI blocks (usually at the first attack you do, since they'll spam after the first block), if you have a heavier weapon (such as a Great Sword versus a Bastard Sword), you will be able to stun them. Directly after the stun, hit. They AI will not be able to block as its hit will be too delayed to work.
- Emergency Horse Brake
When you press Ctrl+J, you'll rear your horse. This is very useful because normally, you'll have to hold down the S key to stop. So you'll NEVER EVER fall into that spearwall because you couldn't brake in time!