This is a pretty simple rule, but, here we go: to the extent possible, fight only one war at a time. Fighting just one war lets you focus your full strength against your opponent, and, thereby, maximizes your chance of winning.

But how do you fight only one enemy in a world with many opponents? There are a few tricks:

• Start away from the action
• Make sure one border is bulletproof
• Back down: if one possible enemy is taking unimportant territories, let them take and hold them. When you win your current war, you can turn around and face this enemy with your full strength.

Fighting on multiple fronts doomed the Germans in two World Wars. Don't make the same mistake!