Counterattacking
Counterattacking can be really useful if you’re being attacked by a huge force but don’t have enough troops to defend yourself. If you counterattack the guy attacking you, you might make him turn back to defend his own village in the middle of the battle instead of plundering your resources. This is just a tip on how to do that.
A easy way to check out how much troops he has at home when he’s attacking you use to look at the number of units he’s attacking you with and his military score. Military score is the number of resources you’ve spend building your army times 0.02. A hoplite takes 70 resources to build so it’s 1.4 points, archer takes 55 resources so it’s 1.1 points, etc. If you’re attacked by say 100 hoplites and 50 archers, that would be 140 + 55 points which equals 195 points. If his total military score is say 220 points, he can only have 220 – 195 = 25 points worth of defense left at home. He can of course have reinforcements from other players, but most often people don’t have that.