If by "change the world" a person means "make the world better," then step #1 must be to decide right then not to make the world worse.
Accidents sometimes make the world worse, and carelessness, and flukes of weather and acts of God. But if a personal decision makes the world worse, then what?
There are different levels of "oops"—didn't know, didn't think, forgot, didn't care, was pisssed off or drunk, was furious and wanted to do damage... What can be undone? What can be atoned for?
The world starts to get better when people stop making it worse, and a person's life starts to get better when he consciously decides to do what is better instead of what is worse in any given moment.
Philosophy, or That's what it's all about!
photo by Sandra Dodd