Everything you do will be insignificant, but it is important that you do it. (Mahatma Gandhi)
Time is short. Start now. Do what you can in your own life. If it seems like sacrifice, maybe it's not time for that part yet. Share what you're doing--and why--with those around you. This may seem hard but it becomes easier with practice. Keep your eyes open for things you can do which will have a wider impact. We don't need everyone doing something, but nothing will happen if we wait for the Right Moment to begin.
Actually, we're all working on Saving the World already--otherwise, you'd not be here reading this. And more is continually being offered to each of us. All we have to do is say yes! And yes, what you do will make a difference.