Humans are much more defensive than Orcs. The Offense Page showed you how to wear the opponent down. This page will show you how to stay alive while using the offense strategies.
Wall-ins are the most common method of early defense. A wall-in is accomplished
by sealing off all entrances to your town with farms (or walls, but they're not as
good, explanation below) and putting a few towers inside a farm wall. That way
his troops have to beat down the farms while they get killed by the towers. This
pic shows a good wall-in if you want to defend your peasants but don't want to
spare the troops.
The above type of wall-in works well against early grunt rushes designed to cut off
your gold supply, but it won't do much for an all-out attack on your troops. For
that you need a different type of wall-in:
Mid game defenseBy the time the mid game comes around your wall-in (or big group of troops) should be holding out quite nicely. Now that you have Knights and Rangers, you don't need a wall-in as much. In the mid game your troops should be able to hold out through most attacks. Make sure to do the +3 for the elves before any other ranger upgrade.
The late game defense is the most important one. There is no time that the Orcs can do as much damage as they can do in the late game. So in the late game you always have to be on your guard.
First of all, reconaissance is essential. You need to know when the ogres are coming. I usually have a line of flying machines covering all the territory from my base to the enemy base. Then I have a semicircle of them around the entrance to my base. That way no ogres can bloodlust without me hearing it, and no ogres can move around without me knowing it. If they do bloodlust off where I can see them, it will wear off before they get to my base. You should never be surprised by any attack.
Bloodlust is the key to nearly every Orc attack. If you can counter it so that you will be on even ground, you will have the advantage. How so? Think about it. If an Orc player did everything exactly the same except he didn't use bloodlust, and you did everything exactly the same, it would essentially be ogres vs. Paladins and Rangers and Mages. Who do you think would win that one? So if you can bring the opponent down to your level, you have him beaten. How to do it? Read on.
As mentioned above, reconaissance is very important. If you have the flier web like I said above, and you do see ogres charging at your base, you can just take a mage or two and cast blizzard right in their path. If you time it just right, it will have much the same effect as the mage bomb. A few will die, and the rest will be hurt severely. Then your troops can finish them off.
Another way to beat bloodlust is similar to what is above, but you cast blizzard while they lust each other up. They won't respond to orders until they are done. Then, you finish them with paladins and rangers.
If it's too late to blizzard them (they're already there), start casting Slow. Since Bloodlust triples the damage they do, Slow reduces it to 1.5 times as much. Then while your paladins fight, have them heal each other. Between Slow and Healing (not to mention Rangers), you should be able to conquer any attack.
Rangers are another key unit in the beating of Bloodlust. They do a lot of damage when they're fully upgraded. If a little more than a third of your army is Rangers, and a little less than two-thirds is Paladins, you have just about the right mix of units. See the build order for a good way to maintain that balance.
It may not do much, but a few guard towers, spaced 4 to 5 spaces apart, can do wonders for a defense system. You should probably wall them in though, since they will fall pretty fast to an enraged ogre.
The final method of beating bloodlust is a simple one, and not very effective. If you have three times as many Paladins as the enemy has Ogres, you will win. However, with all the other methods available to Humans, this should only be used as a last resort. Plus, if you want to overpower the other guy, why not play Orcs and get bloodlust? If you're just going to beat him into submission, you may as well get bloodlust out of it.