The top of the screen will indicate when an enemy will attack. If it is the same type of enemy, the attack order will always be the same. The center will attack first, followed by the left, then the right. Use this knowledge to target your attacks. Try to kill one enemy in the first round before it manages to attack. Consider by starting to attack the enemy troop that will attack last. Try to kill enemies one at a time instead of spreading your damage out to all of them. Enemy troops will tend to attack a specific troop repeatedly. Consider if it is just better to defend or to cast a healing spell on it during the second turn and have that troop healed constantly. It is better to your troops alive instead of spending resources resurrecting them.