Every empire needs a strong, well-defended capital. Your city's buildings are key to your success, and will need to be upgraded regularly. Early on, we recommend focussing your resources on three buildings: your Barrack, Academy and Drill Ground. Upgrading your Barrack increases your troop numbers, their level and effectiveness. The Academy is where you'll develop new technology, but research takes time, so you should start upgrading early. Your Drill Ground determines your maximum troop number, so it's worth upgrading quickly in order to expand your army.