You can begin by making a simple (but not necessarily easy) decision to accept the other person’s position no matter what.
No matter what you think of it, no matter how stupid, irrational, harmful, annoying, or [insert adjective] it may feel to you.
Acceptance doesn’t mean agreement, adoption, or endorsement. It simply means accepting what their position is.
If you can make this decision then you have a starting place, you have ground from which to begin to move towards them.
Without acceptance, you can move in just about any direction except for closer.