Don't produce any units in the beginning, just focus on wood-food-stone economy. Once your allies start getting attacked by the blue you need to send 2 villagers into your allies base and build a castle, stable and barracks and start producing pikemen and light cavalry to help them especially against rams. You can also send them money to produce their own units. The north base will need more help. Standard difficulty: you can focus on gold-food economy and mass produce elephants and target the towers.