Have a mix of weapons to defend your base. Your enemies will be attacking with multiple types of troops.The Domed Defense and Rally Flag are very useful. Both of those defenses are customizable, if you are at the required level. The Dome can be armed with a Sentry Gun, Laser, or Aerial Defense. The Rally Flag can eventually set patrols for six different unit types. Changing what those defenses are armed with is the easiest and most cost-effective method to defend your base effectively.