Time to think about your civilization and exploit it's benefits (though you might have already enjoyed some of them like hunting).
This is the time to start some serious research work. Start from 'Wheelbarrow', which is your first research towards more efficient villagers. Remember, the more efficiently you harness the resources, the more easy it is for you to build a good, well researched army. Consequently, the higher is your probability to win the game. Here again, in some of the civilizations like Vikings have this research done for free.
It would be advisable to start researching from the Mill simultaneously. The moment you finish the farm research and have sufficient wood, get the villagers from wood to farms. Meanwhile set the gather point of your Town Center on a nearby wood resource. Keep 1-2 villagers as builders who will build throughout this age. Build houses, a Market, a Blacksmith Shop and Barracks and a couple of mining camp besides respective resources.
Research fletching from the Blacksmith so that if you are attacked your ringing the 'Town Bell' kill the attackers more effectively. Research town watch from the Town Center to increase your buildings' line of sight (LOS). Research double-bit axe at the Lumber Camp and gold mining at the Mining Camp (stone mining preferable). Research cartography from the Market if playing in allyship. I generally don't use a fortificaton but it is highly advisable o fortify your city and start it right now by stone wall. Try to use natural features such as cliffs and forests as your fortifications as they are quite difficult to breach (cliffs are of course unbreachable unless you use ranged units). Once you are fortified well, you feel secure and your guard towers or ranged units can take care of minor attacks and your resources, i.e. your villagers keep on worling, which is the most essential. "Never leave villagers idle".
After you reach the population of about 40-50 villager, advance to the glorious Castle Age!