Any shoe must be within one horseshoe width (measured across the outside of the open end of the shoe) of the stake to be considered for points. (Official rules call for 6 inches max).
The closest shoe to the stake gets 1 point.
If you have two shoes closer than any of your opponents, you get 2 points.
Ringers are worth 3 points each and must completely encircle the stake so the ends can be touched with a straight edge without touching the stake.
If you have the closest shoe and a ringer, its 4 points.
If your opponent throws a ringer on top of yours, they cancel and no points are scored.
Leaners are worth 1 point and are considered closer than any adjacent shoe except ringers.