When you are building up your town, make sure you don’t place the buildings to close to each other. If you do, you will risk can’t get through your town anymore. They’ll get stuck.

This can be bad, especially when you are being attacked at the right side of your town, while your units (you’ve made to defend) are at the left side. They can’t get trough the town quick enough (or not at all) to stop the enemies.

Another important part is that you don’t forget to surround your town with a wall. When your are building a wall, construct two gates (one at one side of the town and another at the other side), so that your allies (if you’ve got any) will be able to easily get through your town when necessary. Once you’ve constructed a wall, it’s always handy to put some towers (which you can upgrade to a "Keep") behind it, for some extra defense. Some units I always use (and it works pretty well) to defend my town are Archers and Siege Units. Create about 10 archers (enough to protect one side of your town) and some (for example) onagers. Place them behind your wall and make sure you command them to stand ground or else they will run through your gate (the gate will open) and the enemies will get inside very easily.

Most of the time the enemy will bring some (1 or 2) trebuchets (and of course other units) to attack you. Well, defending against trebuchets isn’t that hard as it looks: Very often (when you look at your map, (the little box in the right bottom corner) you can see the enemies coming from miles away. It’s important that you check the enemy’s group of units if there are any heavy siege units coming. If you see (for example) that a trebuchet is coming your way to destroy your wall and other buildings, it’s very handy to create some paladins (a couple of 3 or 4) and send them to the trebuchet to destroy it on his way, before it unpacks.

It comes in very handy when you’ve got some priests, because when your units are in the middle of a battle, they’ll lose health. When your units have killed the enemy units in front of your town, send some priests to heal your units because when the enemy attacks again and your units are not completely healthy, you’ll sure lose the battle. When you’re defending your town and you’ve lost some units in one of the earlier battles please make sure you place the unit you’ve lost for a new one, because otherwise your defense will get weaker and weaker.

So, you’ve got to try to keep your units to defend, but of course at the same time it’s necessary to create units for a possible attack. A lot of people are very busy with defense and they forget about the attack. It’s pretty hard to keep up you’re defense when your creating attack units or when you’re building up your town. Some short tips:

1) Try always to watch your mini map in the right corner, because you can see the enemy coming form miles away when you look at it.

2) Make sure your units pile stays the same. It’s very dangerous to defend your town with a little group units and it’s also not advisable to defend with units with a low health.

3) Trebuchets and heavy siege units are a very nice way to attack a town, so the enemy won’t attack without them. It’s important to destroy those units before they’ve reached your town, because if you’re too late they’ll destroy every building and unit you’ve got.