South America first. Then I work my way to Australia. Africa is easy to destroy from South America. Then you move on to Europe. With the troops every turn from Australia, Africa and South America it is easy to make Europe fall. From there you must do a pincer attack on NA. Europe will not last long against an Asia - NA 2 sided attack. Get a path from Europe to SA through NA to move troops. Now you can let Australia fall once NA is taken over. Let them waste troops taking that over. While you reclaim Europe and amass troops to take down Asia. All out attack on the boarders. You win.