Sacrifice of the self, at the core, means sacrifice of your own mind to the mind of another (or others).
This automatically sets into a motion a motivation of caring about what others think, because the primary standard becomes HIS or HER or THEIR minds rather than your own. Thus, getting the focus back to “What do I think of HIM/HER?” and away from “What does HE/SHE think of me?” will do a lot to help.