Identify the stereocenter
Assign priorities to the four substituents using CIP rules
Compare the atoms directly attached to the stereocenter
Higher atomic number gets higher priority
If the directly attached atoms are the same, move outward until a difference is found
Treat multiple bonds as if the atom is bonded to equivalent duplicate atoms
Orient the molecule so the lowest-priority group points away from you
Trace a path from priority 1 to priority 2 to priority 3
Clockwise path = R
Counterclockwise path = S
If the lowest-priority group points toward you, reverse the result
For Fischer projections, vertical groups point away and horizontal groups point toward you
For wedges and dashes, dashed bond usually points away and solid wedge usually points toward you
Assign each stereocenter separately
Do not confuse R/S with D/L or with optical rotation (+/−)