How many times have you heard someone say that they bought a new sofa...
and then had to redecorate the whole room? It just doesn't seem possible to replace our kitchen appliances without doing the counter tops, which then leads to flooring, wallpaper or paint, and window treatments.
The same thing seems to happen when you have the money to decorate only one room, and then are dissatisfied with any adjacent rooms.
The secret to doing this successfully is to integrate your new ideas and desires with the existing ones that you cannot change.
For example, if you are really happy with the color scheme in your dining room, but no longer want a traditional look, draw the colors from that room to your living room, but replace that traditional sofa with the more contemporary one you are craving.
If you have sheers and tie-backs on the windows in both rooms, you might change the shears in the living to vertical blinds, maintaining the same color, but giving it a more modern look that will go nicely with the new sofa.
If your love the paintings in the living room and they are framed in heavy gilt that was perfect for your traditional look, but inappropriate for the new look, change the frames.
Obviously you cannot use chrome frames on a Rembrandt painting, but you can change to a simple wood frame that would be less extreme.
Are you planning on eventually doing the dining room as well? If so, keep that in mind when you choose fabrics.
If you want to keep that dining room set, will you want to change the fabric on the chairs to go better with your new sofa? If not...
be careful what upholstery you choose for that sofa!