Kumar said:
you forgot 1 great RTS...Dawn of War!
be it AOE or DOW while playing with friends, we assign one player as a resource maker and we defend him...basically his job is to create resources and pass them on to the other players and in turn we defend him.
That strategy is called sling shot and can be applied while playing againist human players or computers.
Talking about strategies, I can tell you about AOE Hardest difficulty AI. Basically the hardest difficulty AI cheats the player to get an upper hand. What happens is that the AI player gets free extra resources (In addition to what the AI collects through its villagers) at regular intervals and this try to overwhelm the opponent.
The key to cope with such an AI is to attack it very early and try to finish it off. i.e Any sort of Feudal or early Castle age rush is required here. the AI player will be vulnerable before it starts building walls and this is the time for you to attack. once it builds walls, it will become almost impossible to cope with the AI players attacks. I usually use Feudal age rushes againist hardest AI (i.e Archer rush, tower rush) or even castle rush. The problem with these rushes is that if you cannot destroy the AI before it builds walls, you get into a pretty vulnerable position. Another alternate is to use a semi defensive/offensive style of play. I get to castle age fast and build a castle in my base and start to pump out castle units, then build another castle near the enemy base and start attacking. The castle in my base is a defensive measure.
In team games againist computer AI, the strategies become more diverse. Me and my college buddy defeated 6 hardest computer AI (teamed together) in AOE 2. We both got picked up Huns as the civilization and started farming massively. We used castles for defense of our bases and Hussars as the offensive unit (This is a food only unit). Huns have several cavalry bonuses (like faster stables) and we made use of that. We covered the map with stables where ever we could and churned out Huassars by the hundreds and overwhelmed the AI players. Since 6 Hardest AI are teamed together, we had to take the defensive and destroyed base by base.
Another thing we took advantage of is the fact that the computer AI attack only the player with he highest score. If the AI is attacking you, try to deliberately decrease your total score, once its lower than your team mates, the AI units will stop attacking you and start moving towards your team mate. your team mate has to do the same thing. so basically you keep the AI units spend more time moving in between you two than in destroying you. This requires a bit of coordination and if you pull it off properly you can ensure that your bases stay safe while at the same time, you can put together a small army that keeps attacking the enemy bases.