After the big major themes, you can write small. What is the typical day in the life of your character? How did people dress or wear their hair?. Think about the food of the time. Were people hungry? Were certain things rationed? Drink? Music? Art? Those are all important aspects of daily life. What was the price of theater ticket? A glass of wine? Find one or two things (tangible and small) and write everything about them.
Four Historical Fiction Writing Hacks – DIY MFA Blog – Constance Sayers