Medieval II: Total War

If you are playing with a faction that can recruit horse archer units (Turks, Egypt to some extent Hungary) make an almost full stack of horse archers with one or two generals. Having a full cavalry army allows you to jet around the world map and pick the place you want to fight or just avoid anything you can't handle with your superior speed. On the combat screen just kite enemy army until a-)enemy troops start to break from massive losses b-)ran out of arrows. Charge in with your cavalry and bodyguards, the enemy will break. Chase them around with your fast horse archers and let none survive. Walk around with couple of spies(they can match your army speed) to open the city gates or just hire some basic infantry to siege.

Increase the fun by landing on far to reach areas like Spain or England and raze every city. Since they can't practically invade you rack up experience and cash.

If you are playing with Turks(or any faction that can call Jihads) you have a 5 piety imam from the start. Call for a Jihad against a neutral\poorly defended city you are about to invade(Smyrna for instance)at the first turn and have all your commanders stack in same army before joining the Jihad. Recruit anything you can on the way, invade the city and voila! You have a full stack of experienced troops, Holy Warrior stat on your commanders, Chivalrous Knight retuine for everyone participates, over 4000 cash from successful jihad plus the gains from city.

Around somewhere in Eastern Anatolia you can recruit Elephants and War Elephants as mercenaries. I'll even go there with my British faction no matter what.

Warning: the above items might be invalidated by the Kingdoms expansion pack, take them with a grain of salt!

You have two basic modes in Total War games - the World Map and the Battle Map. World Map plays very similarly to the Civilization series in that you manage construction for your various cities and try to keep the public happy while you move your armies around. Once combat is instigated, you can auto-resolve as a Civilization battle would do, but that's no fun. You want to fight the battle in real-time.

You'll go into the Battle Map and you can array your troops in formation before starting the battle. Once you do, the game plays out very similarly to an RTS. The main difference is that you can only control massed units of 60+, not individual soldiers. You'll have to use tactics like troop counters and flanking a lot in battle. If things go hilariously/horribly wrong one side, then a few of their units will start to rout. You won't be able to control them, they'll just run away in panic. Total annihilation of the opposition rarely happens in Total War; it's a rout that you're aiming for, so make sure to damage enemy morale as well as enemy numbers.

Lands to Conquer is probably the best mod to start out with, as it's basically a refining of the vanilla M2TW experience.

After you're more comfortable with it, I'd suggest Stainless Steel. It adds quite a few factions and alters the gameplay pretty drastically. Some people have reported instability problems with it, however, even though I've never experienced that.

I'd also like to mention a less popular mod called Thera, which is a kind of alt-universe historical fantasy mod. It has a new map and rearranges the factions, and even includes a Roman faction that another modder apparently made. It's still a bit raw, but it's pretty interesting once you've played the hell out of Europe and want something different.

Try not to ally yourself with your neighbor, and instead ally yourself with the neighbor of your neighbor. Your immediate neighbor is for you to conquer, and your new buddy next door to them will be able to help out. So if you're playing as Byzantium, make an allegiance with Milan and start a war with Venice.

Each of your generals has stats that affect gameplay - Command, Loyalty/Authority, Piety, and Chivalry/Dread. Command only matters if you auto-resolve battles; the game engine compares the size of opposing armies and the Command rating of the generals in control when determining who wins. Loyalty measures how likely they are to defect versus your current king's Authority - the higher both stats are on either end, the better. Piety is good to keep high as well, otherwise they might be targets for inquisitors. Stats that people often neglect with their Generals are Chivalry and Dread. If a bonus is given to one, it detracts from the other. So if your general acts like a dick in battle - executes prisoners, exterminates cities, hunts fleeing armies down - then his Dread will increase and his Chivalry will decrease. His Chivalry will increase (and his Dread will decrease) if he's a good guy. Concentrate on making your generals into either a total bastard or an angelic saint, as their other stats will increase accordingly if their Chivalry or Dread is high enough.

If a Guild wants to set up a branch in one of your cities, remember that no other Guild will be able to set up there afterwards. Some Guilds are way more helpful than others, depending on your situation - a Theologian's Guild isn't going to be of much assistance if you don't need Priests that much, but a Knight Order chapter house will give you some ass-kicking new units to train.

Build towns in your inner territories and castles on your frontiers, and turn your outside into a ring of military production while your inside serves as the main source of income for your kingdom.

Always be sure to keep the people in your city happy. You're able to tell what's currently pissing them off in the city menu, and you should adapt construction accordingly.

Each faction has its own specialty on the battlefield. France's cavalry is superb, for example, whereas England has fantastic archers and Denmark has fantastic heavy infantry. When composing your armies, the "star" unit of your faction should play the main killing role, while the other unit types should be balanced appropriately to support the star unit. So when playing France, have your mediocre infantry and archers tie up the enemy while your cavalry swoops around from the rear and bulldozes them over.

That reminds me, always try to flank, especially with heavy cavalry charges. If you pull it off, it's incredibly destructive.

The hardest part of besieging a settlement is getting through the walls. For besieging, make sure you've got an army with lots of infantry and archers. Heavy cavalry will dominate open battlefields, but they're mostly useless in sieges until the gates are down. Infantry and archers also work well in manning siege engines, which you should always build more than one of; they can get destroyed fast under an especially harsh flaming arrow volleys. You can also bypass siege engines entirely if you have catapults or cannons, but remember that their ammunition is limited, so make sure you've got plenty if you're going to assault a high-level castle. My personal favorite method of assaulting a city is to sneak a Spy inside first, and camp outside until he's able to open the gates for my army.

Send your horse archers/light cavalry to deal with enemy catapults/archers. Eliminating your opponents ranged forces balances the playing field if you're outnumbered.

Ignore merchants, waste of time micromanaging them and they always get destroyed by enemy bean counters. Useless until your empire is big enough to have them be in any territory you want, at which point you probably don't need the money anyway.

Upon capturing a new territory, make sure to demolish any remaining buildings that do not belong to your religion.