What is the essence of a space?
One of the things you struggle with when redesigning/renovating a home is defining what it's supposed to be and where it needs to go.
If you were creating a theme in your property, this exercise might be the first step. You have to strip the project down to it's essence (easier said then done) to know what to do.
There's a lot of ways to look at this.
Historical
Feeling / Emotion is another way to do this.
Architectural Features - essentially working with, not against, what you've got
In the space, ask yourself, what do these architectural features (assuming I'm not changing them) want me to do?
If you have really low ceilings in a portion of the home, it's probably not an area you want to be attempting "grand," or at least grand in terms of the hotel lobby sense of the word.
This might be a better space to think more along the lines of den, or lounge or intimate guest room.
Bridges
Some rooms/spaces are nests. And some are bridges.
You start by considering what is the "flow" from room to room. How is life lived in this space?
An example in my home is the living room (sorry for no pictures). When you walk in our front door, you walk right into the living room. The "path" to the rest of the house is directly through the center of the living area.
I don't love this but I make it work. Although I would prefer a living room that created a U shape or a square where people could converse across from each other, it's simply not possible.
Our front living room functions primarily as a bridge into the rest of the house.
It's why we created a second living area. A more formal room, tucked away where you can feel enclosed and the path is in, but not through the room.