Indoors Plants
Adding a few unique natural indoors plants is a good idea.
Layered Shelves
Installing layered shelves is known to be one of the best decoration idea.
Paint Furniture
If you couldn’t paint the walls of your room then painting your furniture can be a good option. Painting a furniture would give your room a fresh look. 
Fabric Boxes
We mostly have an overflow knick knacks that we want to hide. You can place fabric boxes to place these overflows.
Patterned Carpet
A patterned carpet under then feet can play a neutral furniture role.
Sheer Curtains
To get maximum natural light you can replace heavy fabric curtains with sheer curtains.
Horizontal Flaps
You may have seen vertical flaps installed at your friends house however changing the direction of flaps can also be a good idea of decent look.
Balanced Colors
Color combination is a huge topic to cover. You can place one prominent furniture element while keeping the rest of the elements light.
Gallery
A grid view of gallery can also be a good idea to decor room or hall.
Black and White Color Combination
The modern room also uses black and white color combination with modest lights.
Thanks for great ideas! Modern design is one of the best ways to increase the value of the house.