The initial build order is:
P1 – Hall … Farm … Walk to expansion . Hall … Gold
…………………………P2 – Farm … Walk to expansion . Farm or barracks
After making your initial farm, you wander to a nice expansion spot (generally L1, L3 or L4) and make another hall. The next step depends on what method you take for defence.
For a catapult defence, make a large open wall-in at one base, utilising a smith, a rax, a mill and 3 farms (initially). At the second base make a hall and a rax. Spend the rest of your gold on peons (which mine gold) and another two farms. When you have around 13 peons, stop spending gold on peons and make a catapult at each base. Try to build in a way that minimises the area of buildings that is exposed to enemy attack, and maximises the area exposed to your repairing peons. You will be swapping your view between bases a lot, so it is a good idea to assign your main town hall to the ‘0’ hotkey (press ctrl-0), and your expansion town hall to the ‘9’ hotkey. Then just press twice on ‘0’ to centre on your main base!
Early on, if the opponent is rushing, there will be a few grunts attacking your buildings before your cats are built. You will be fine as long as you left enough room for at least two peons to repair the building. Don’t waste any time starting the repair process when you are attacked. If it looks like the building will be destroyed, make a new one behind it in such a way as to preserve the wall-in. Once the cat is built, make it attack into the densest part of the grunt mass, and keep reminding it to attack, as the AI is not particularly effective.
The inside-cat has several advantages. They have long range, making them useful against offensive towers. They can kill a level 1 grunt in one shot. They are manoeuvrable, meaning they can be repositioned if the wall-in is broken, and they can be relocated (slowly!) to defend an expansion. They are cheaper than a cannon tower. Their disadvantages are that they are slow to build, and are practically useless if enemy troops get access to them. They require a barracks and it is often impractical to build a barracks in such a way as to allow the cat to appear on the inside of the wall-in.
The other defensive option is towering. Make either one or two arrow towers or a single cannon tower at each base. The advantages of towers are that they are cheap and don’t take up much room. You can wall in at some spots with a single farm and build a tower inside. Their disadvantages are that they may not have enough range to protect against an offensive tower, and are vulnerable to offensive cats and Sappers. If you want to save resources, don’t upgrade the tower until you are attacked. The risk here is that the enemy could break in by the time the tower comes into effect.
In either case you will probably want to have one or two peons left on the outside after you have walled in your main and expansion. These ‘outside peons’ are used to make more farms (within range of your defences), and later on to build barracks when you are ready for mass troop production. You can use one outside peon to scout the enemy and see if they are rushing or walling-in. If they are walling in you do not need to bother with as much defence (e.g. don’t upgrade towers yet). Scouting the enemy will most likely result in the loss of that peon. It is a good idea to keep one peon hidden in a remote part of the map, possibly making farms unless your opponent is a good scouter. It is quite reasonable to not leave any peons outside, as this will increase your initial resource flow, which is quite crucial in the early stages of a 2-Hall build. The main disadvantage here is that you will not know what your enemy is up to unless he rushes you. If you see a grunt attacking your base, check its upgrade status. If it is level two or three, your opponent is probably rushing. If it is still level one when you have some defences operating the opponent is probably not rushing (or is rushing badly, which is even better!).
You need to make a grunt or two keep an eye on your opponent. If you were scouted early and didn’t face a heavy rush, the enemy will probably be preparing to break into one of your bases. This will normally be with two catapults and grunts, or with an ogre/sapper attack. If your barracks was built in a position to allow a catapult to appear on the inside of your wall-in, make a farm or two in order to block the parts of the barracks that would allow units to appear inside your wall-in.
Once you have some defence, get back to making peons and farms. Get some peons on wood at the same time. Once you have about 23 peons and 1000 wood, upgrade to stronghold at your main. Get the sword and shield upgrades while you are getting the stronghold. If you do not have any outside peons, chop out of your wall-in, whilst making it easy to re-seal once you have a couple of peons out. Keep making peons at the exp and your resources should really be flowing by now. Repair build an ogre mound inside the main wall-in, and make two more barracks at either base. Be sure to have enough wood peons to have 1250 wood ready to upgrade to fortress when your ogre mound is completed. If you don’t have enough wood then delay the third barracks. When you have started the Fort upgrade, start making Ogres as fast as you can. When you have spare resources put up an Alchemist and make a Zeppelin.
Before you upgrade to fortress, you should have an idea of what the enemy is doing. If you discover that the enemy did not hastily upgrade to stronghold, but made a mill, you could face two cats. Build an extra cat in your base and make outside grunts or ogres at the base not being attacked. If the enemy is quick to upgrade to stronghold you could face an early sapper attack. In this case scout around for a nearby alchemist. If you have a cat defence, get ready to re-wall when a sapper destroys your wall-in. Have a peon waiting beside the part of the wall-in you think is most likely to be sapper-attacked. If everything goes well, you will be producing ogres by the time your wall-in is broken, and your production will already be superior. If you have a tower defence build two or three extra arrow towers. In either case, if one of your bases goes down, you may still have enough resources to win from the remaining base.
As soon as you have upgraded to fortress, repair-build an Altar and make two temples. If you are still mining two mines and the enemy has only one, you should have little difficulty from here. Make more barracks until you have at least five, and overwhelm the enemy with vastly superior Ogre numbers, backed up with deathknights.
If the enemy was also two-halling, then you could have an even fight on your hands. The key here is to expand two more times, do not think you are bloated with resources that will see you through to the end of the game. At the same time, try to limit the enemy to a single expansion. Make Zeppelins to scout. Patrol one or two over the empty mines, and keep one watching the enemy troop production. You can win from here either by starving the enemy of gold or by destroying the enemy’s barracks. You can lose by letting through a couple of dk’s to kill your gold mining peons, or by being caught out with unlusted ogres when the enemy attacks you at your main.
Use similar tactics as described in the rushing scenario, adapting to the fact that there are greater numbers of units on the battlefield.