I don't mind all the grey colors ... there's just not enough contrast between the objects.
Adding shadows would, I think, help to seperate the bed and other objects from the floor. With a "top down" perspective like this it's easy to lose which objects have "depth" if you don't have shadows.
Also, I think a Zelda style perspective on the walls would help pull this image together.
Here's a [ very ] quick paint-over to show what I mean:

- added perspective to the walls
- moved bed and desk stuff "up" the walls to add depth to them.
- added a door
There'd need to be some depth added to the steps as well but I didn't have time to do that! I hope this helps!
Adding shadows would, I think, help to seperate the bed and other objects from the floor. With a "top down" perspective like this it's easy to lose which objects have "depth" if you don't have shadows.
Also, I think a Zelda style perspective on the walls would help pull this image together.
Here's a [ very ] quick paint-over to show what I mean:

- added perspective to the walls
- moved bed and desk stuff "up" the walls to add depth to them.
- added a door
There'd need to be some depth added to the steps as well but I didn't have time to do that! I hope this helps!