In this era your main objective is to collect food! Also, you will need to colect a bit of wood too to construct buildings and explore the map with your scout.
Why the major objective is food? In this era you only have one military unit avaible, the militia, a very weak unit. So, usualy you don’t want to atack your enemy with this unit, you want to advance as quick as possible to the feudal age that has more and better military units.
So, in dark age you want to queue new villagers without stop, to increase your worker base, collect 500 food and advance age. Each village cousts 50 food, the magic number of vills gathering food to allow for a constant queuing of new ones is 6 on food.
When the game starts you will:
To advance to feudal age you will need to build two dark age buildings – a lumber camp and a mill – and pay 500 food. Usually you want to advance to feudal age when your total population (vills + scout) hits 21 pop – around 8-9 minutes.
In this age, you now have much more military unit unlocking acess to Barracks (man-at-armsn and spearman), Archery range (foot archers and skirmishers) and Stable (scouts) – this could vary between civilizations. So, this is the era when the agressions between opponents starts.
In this era your objective will be usually two options:
Don’t forget to remain continuously queueing new villagers and to research the economic (double bit axe and horse collar) and the military (blacksmith) upgrades.
Rush the enemy: Usually, build an army of scouts, man-at-arms or archers to attack your enemy, killing their villagers to damage their economy.
Go for fast castle: Wall your base and create some defensive units. To advance to Castle Age, you will need to build two Feudal Age buildings – usually two of stable, archery range, blacksmith and market – and pay 800 food and 200 gold.
In this era your objetive will be to upgrade the army and expand the base.
Economic aspect: expand your base building new town centers in strategic resources (gold, wood, stone) and locations (hills). Usually, drop 2 new TCs (total of 200 stone coust, paying with the initial resources) to triple your villagers production and, consequently, your economy.
Don’t forget to remain continuously queueing new villagers and to research the economic upgrades.
Military aspect: upgrade your army researching the upgrades (on blackstmith, stables, barracks, archery ranges, university and castle). You also gain acess to the siege workshop to create siege units. In this era you unlock the castles; build then in strategic resources (gold, stone) and locations (hills). Castles also unlocks your civilization unique military unit.
Don’t forget to continuously build houses (because your units villagers and military units production will grow really fast) and to research the military upgrades.
TIP: don’t forget to research ballistics (in university) for your ranged units.
Also, start constructing more military buildings outside your base to gain map control (with visibility) and to enhance your production capacity.
Build a monastery to collect the relics around the map. They give you gold per second and are extremely importante when the gold mines become escarse.
The coust to advance to Imperial Age are 1000 food and 800 gold – very expensive. If your enemy has just advanced to the imperial age, it could mean that he was saving resources to do so. It might be the ideal time to attack him, picking him up with a small army.
This era is an upgrade of the same objectives of the Castle Age: upgrade your army and keep expanding your base and economy.
Don’t forget to remain continuously queueing new villagers until you hit aroung 140 villagers in total, leaving 60 pop to build a great army. If your army dies, the 140 vills collecting resources will enable you to rebuild your army very fast (with a lot of stables, archery ranges… around the map).
In imperial age you unlock a very strategic unit, the trebuchet (in the castle). Use them to destroy the enemy buildings, especially castles and town center, at distance.
TIP: don’t forget to research quimic (in university) for your ranged units. This upgrade increase de damage of arrows and unlock the gunpowder units.