1. Fight a lot of wars.

Experience is key! The more knowledge and experience you have in something, the better you will be at it.

2. Third-party on them.

While the other two parties have already been worn down from fighting each other, you can jump in and quickly take both of them out! (Famously used in the Chinese proverb 鹬蚌相争)

3. Flank them.

The oldest trick in the book.

4. Ambush them.

Catch them by surprise, and take them out while they’re still dazed.

5. Get an ally.

Strength in numbers!

6. Betray them.

They’ll never see it coming.

7. Fund a revolution within them.

Internal revolutions are horrible on their own, and even worse when you’re fighting another war at the same time.

8. Destroy their supplies.

No supplies, no power. An army can’t fight on an empty stomach, and guns are little more than blunt objects if they can’t shoot bullets.

9. Take out their leaders.

Without leadership, the entire army falls into disarray.

10. Nuke them.

Kaboom.