One thing to pay close attention to there is what makes the kingdoms unique besides just the type. What are the different cultures and religions? What are their holidays and celebrations and customs? What types of food do they enjoy at feasts? What guiding principles do the people of each kingdom follow?
For example, in the magic kingdom, there could be a large focus on education, with a lot of pressure on young men and women to attend prestigious academies. A down side to that could be social consequences if a person is unable to get into one of these schools. On the other hand, the barbarian kingdom could put more value in strength and courage and physical discipline, and they could scorn those who spend too much time with their noses shoved in a book. An inspiration for the difference between these two could be Athens and Sparta in Ancient Greece.