When someone enters your room, the first thing that their eyes see are the walls. Walls reflect your creativity and so you can do with them to decorate. Decorate your walls with sticking butterflies or different art pieces.
Paintings might always be evergreen trend, try these 3-d art pieces. These are made up of metals and these are highly durable. One of the best part about these artpieces is that these are highly affordable. You can order them from amazon at just 300 or 400.
You can also show your creativity by placing them in different patters around various objects.
I have just added the images of some art pieces but you can try out with different other traditional designs to theme your house and room according to the event and Diwali.