You can indeed change the world. Every single good thing you do can change the world.
You can change your home. You know that. You do it every day.
Sometimes when we see or hear of a need, there is nothing we can do to help. Sometimes the only thing we can do is pray. But never underestimate the power of the prayers of the righteous.
Stop looking in the mirror and start looking out the window.
We are to serve everyone we encounter, even those who we might consider "the least."