1) A good general must know his surrounding.
2) a good general know his plan and future action
3) You must always try to deny enemy from reinforcement from captured territories and money income.
4)If your soldier was turn-block, it is the fault of the general.
5) if your tank failed to kill a militia, it's the fault of your soldiers.
6) get a ally before you enemy, for you will learn of your enemy's plan and power from your secret spy who is your enemy's fake ally.
7) ALL WARS ARE DECEPTION!
7a) make a city look defenseless, but reinforce the city next turn to trick your enemy into a trap. this technique doesn't always work but it's a good try for useless city that you forgot to wall or on purpose.
8) Always try to get more allies to your side. you could impose rule 7 on this later on, if your heart is full of evil.
9) war is not always winning a battle. it's about how you win the battle.