A common yet effective routine is:
Seated Press 12,10,8,6
Upright rows 12,12,12,
Lateral Raises 12,12,12
Rear Laterals 12,12,12
Barbell Shrugs 12,12,12
Thats the main and basic idea. Some people like to use Dumbells for their primary exercise. I personally think every shoulder workout should have Lateral raises and Upright rows.