Identify the double bond to be assigned
On each alkene carbon, list the two substituents attached directly to that carbon
Compare the directly attached atoms by atomic number
Assign higher priority to the substituent with the higher atomic number on each carbon
If the directly attached atoms are the same, move outward atom by atom until the first point of difference
Treat multiple bonds as if the atoms are duplicated or triplicated for comparison
Compare the highest-priority substituent on the left alkene carbon with the highest-priority substituent on the right alkene carbon
If the two higher-priority substituents are on the same side of the double bond, assign Z
If the two higher-priority substituents are on opposite sides of the double bond, assign E
If either alkene carbon has identical substituents, E/Z notation cannot be assigned
Apply the same comparison to each stereogenic double bond separately