Using Props to help you write
Here is an example of the imagination process for me. In the second book of my trilogy Gabriel will visit the house of Ullender, a man who lives in the city of Halas. When i did my first draft the house was poorly formed in my mind, if Gabriel needed to exit a room, suddenly there it was in my mind. When he heard a sound from someplace else, I was never sure why the sound was being made etc.
Enter some cardboard, tape, blutack, and a figurine or two. It took me a few hours to make this, but now I have a very vivid idea of the house, what goes where etc. The houses in Halas borrow from Roman architecture in many ways, the floors or all tiled, some (namely the family atrium) has mosaic tiles. But Halas isn't locked in Roman period at all, there is an icebox in the courtyard, they have functional plumbing and pipes throughout the house. The water grooves under the beds are even connected to this plumbing. Ullender is middle class, and he lives with his wife Gelli and their children Alona and Wendel. Ullender's parents and Gelli's parent also live with the family, and it is Ullender and his father Churot that operate the carpenters shop that provides for them all.
When Gabriel comes to the house he is given a room upstairs with strict instructions to keep the windows closed. To say why would be a spoiler....