Start by surrounding your capital by unlocking the areas around it. Each empty tile you conquer costs you a coin. Focus on finding cities and taking them over to increase your income. These cities are your main source of income. You can also search for balloons that can land on any invisible tile on the map. Try to get as many cities as possible before contacting the enemy. Use your income wisely not to run out of money. Upgrade your lands to increase their durability and protect your capital. Surround the enemy capital by conquering the lands around it, and win the game.