I like to start with these 5 principles and then work from there.
1. Define A Focal Point
In this room the primary focal point is the fireplace. The furniture is placed parallel to this wall. Floating away from the window wall and the 2 klismos chairs floating across from the sofa.
Even in a small room the furniture most not block your everyday walk through of the room. Decide how you move through the room and leave space.
3.
Create more than one Conversational GroupingYou want to create as many groupings as you can in a room. This allows you to use the whole room not just the area around the focal point. In this room there is the sofa seating area and the area in the foreground with 2 chairs. There is also a desk and chair area behind the sofa in the corner.
This trick keeps the room interesting and lively.
Float the furniture if possible. There is nothing worse than an empty middle space in a room. Use ottomans or cubes to provide additional seating in a empty space.
I love to use draperies or screens to define spaces. You can easily create different areas of function and privacy.