Improve your base early in the game. Build all possible structures and upgrade them as often as possible. The single player campaign can become difficult quickly. Only attempt conquering other bases after your own base is set up properly. Use the free time boost that becomes available after there are five or less minutes of building time whenever possible. Defending your base is best done through proper design. It will not be possible to have everything protected by walls and defensive buildings. Instead, position defensive buildings around your Town Center and surround them with walls to allow them to stand longer. Keep the resource buildings within sight to bait your enemy. An opponent cannot use the target too many times in battle. Try to reach to the Medieval Age as fast as possible to have gain more defensive options. Build them first and only upgrade them afterwards. Towers that are under an upgrade will not provide their bonuses if you get attacked. Try to time upgrades when you have a peace treaty.