I think that you need mostly white, but something in a print that incorporates your colors. Perhaps pillow slips or at least a mostly pea green painting/poster/wall-hanging that also has some brown, perhaps in the frame. You could also do a stencil on the pink wall using the green paint, some white, and some brown. How about a nice tree branch? You can also buy vinyl decals from Etsy or other places--not sure that you could get pea green, but brown and white should be available.

If you want to highlight the staircase wall then your could use earthy colours such as a yellow ochre! The wall could be enhanced even more by using suitable frames and making a good collage composition for all the photos that you have (I can see many lying on the dining table). This colour would match well with wooden furnitures

Hi Cynthia, thanks for your comment. I still haven't decided about lighting. First, I'm trying to get as much natural light as possible. If there are still some dark corners left, then I'm planing to use light on those areas.

Hello Vipin, As the floor is dark green I would suggest a biege sofa, a very very light yellow colour for walls, light yellow and biege plain self designed alternately placed curtains, brighter yellow and dark green (as that of floor)alternating cushions and an orange base painting with white yellow and green on it on one wall.Hope my suggestion is of some help to you.