Originally Posted by
Sitalkes
You seem to be having a problem with being outnumbered and posessing the wrong units. There are several guides available though none would address this problem specifically. Firstly you need to know that, other things being equal, spears beat cavalry, cavalry beat swords, and swords beat spears. Axes/two-handed weapons are best used for flank charges but have a chance against most things (especially if they are armour-piercing). Bows and other shooters get beaten by pretty much anything but especially cavalry but arrows are especially effective against spearmen and cavalry. Javelins are good against armoured targets and elephants. Walls are best defended by swords and bows/crossbows as larger weapons are not supposed to work very well in that environment.
If you lack certain unit types, think about what combination of troop types will make up for the deficiency. For instance, if you lack good heavy cavaly then consider using spearmen backed up by archers to counter the enemy cavalry. When charging into a cavalry melee, throw in some armour-piercing infantry and they will likely tip the balance in the favour of your inferior cavalry. If you lack shooters then you have to advance onto your enemy as fast as possible and hopefully you have enough cavalry to just charge down your opponent, preferably from the flank so you don't get shot up. Same thing if you lack heavy infantry, hopefully that means you have more cavalry and they love charging down heavy infantry (not spearmen).
Having fewer troops means you have to guess where the enemy will deploy. They will usually deploy on the highest ground in their deployment area that corresponds to their deployment on the strategic map. This means that if they are on your right on the strategic map (look at the brown blobs) that is where they should be on the battlefield (though they do cheat and deploy on the highest ground regardless sometimes).
Now you know where they will deploy, deploy your army so that it can achieve a local superiority (could be firepower or cavalry superiority) and overwhelm one flank only of the enemy army. Then you roll up their army from that flank. You have to move fast to make this work. Try to make your attack a downhill attack. Remember the AI will make its strongest attack on your left flank as it puts its best troops on the right. The best option is to get in a downhill attack on the enemy right flank as although that's where his best troops are, they are extra vulnerable to flank attacks on that side as it is their shieldless flank.
For instance, you have only two cavalry to the enemy's four cavalry units. Deploy both your cavalry on your left flank and attack the enemy cavalry facing them - they will be two versus two, which is much better odds. Give them some shooting or spear support and you are certain to have victory on that flank, so you can sweep around and start destroying the rest of the army.
When you deploy your army, group it into spears/shooters/cavalry/heavy infantry/artillery. This helps decide how to place them - you can then ungroup them and they will stay together in their troop types. if you have hilly/mountainous or forested terrain you can put your troops in a place where their smaller numbers don't matter eg on top of a steep hill or in a gap between woods.
How you line up your men depends on your battle plan. having grouped your men into their respective troop types you can easily see what sort of battle you want - are you going to wait for the enemy to come to you (you have a lot of shooting power and a hill) or are you going all-out for an attack, or is it a flank attack or envelopment you want? I usually spread my troops out as much as possible to create more opportunities for a flank attack so only a single line is enough unless there are some troops that need protecting such as shooters in danger of cavalry attack. I have also on occassion jammed my entire army into the farthest corner of the deployment area, stacking one unit above another, so they can fit onto the highest ground on the map. There is no one solution, you have to know how to take advantage of terrain and maximise your advantages in troop types.