After stockpiling enough resources, consider building your defense. You will not have to worry about defense any earlier, as you will not be a target of other players if your resources are meager.
Resources
Start by building your resources. There are four different resources that correspond to a particular district: lumber, food, ore and stone. You can maximize your resources by upgrading districts by upgrading structures.
Upgrades
As you progress, you will have many things to build or upgrade. Managing your builders may become difficult. Keep your researchers, builders and recruiters working together at the same time. This will allow you to make rapid upgrades, as well as improve every element of your realm. Base your strategy on how long tasks will take to complete. Use things that require a shorter duration if you are planning to play actively. When logging out for awhile, set tasks that require a longer time to complete.