1) International intervention particularly by Britain and France was crucial to both sides of the conflict. Either one of these European superpowers intervening directly would have almost certainly altered the course of the war.
2) A more aggressive and decisive strategy by the Confederacy early in the war could have allowed them to secure their borders earlier.
3) A split between Northern and Southern Democrats could have weakened the Union’s ability to prosecute the war.
4) A diplomatic settlement between the North and South could have brought an end to the war before the Confederacy was completely defeated.
However, it is important to remember that the Union had several advantages over the Confederacy, including a larger population, more industrial resources, and a more experienced military. The Confederacy would have needed to overcome all of these advantages in order to win the war.