Flooring and Wallpaper
Give the flooring a new feel with some nice new tiles or a soft carpet or even wood. Put whatever suits and feels good for your sims in slippers looking out the window on a frosty morning. Now with their new flooring their wallpaper looks out of place so change it up a bit, add a feature wall and experiment with different textures and colours to see what works and what does not work.
Sometimes you may be really keen on brick walls and use them for your sims home and then the next day you may be disliking that and using wood panels instead. It is completely your choice and what you feel like putting and if it is suitable for the style that you are going for.
Furniture
So you might want to put those curtains you took down and stored away back up seeing as it’s getting colder outside and we don’t want all those drafts coming into the house. If you don’t have that much money left then you don’t have to go all out. With all new furniture for everything you can just change up the colour scheme, change the layout of the furniture and transfer some things from some rooms with other things from other rooms. You would be suprised with how much you can change and do to your sims' properties for such little amount of money. Of course if your sims' furniture is too old and tired then get some new furniture to replace it. If the house still isn’t quite working as you intend it too then maybe removing and adding walls would be a good option. Don’t forget that there are half walls too to change the atmosphere.
AFTER