Start with decluttering. Take two buckets or boxes.
Now in one box start putting everything you will throw right away. And start picking up from one side.
In the second one put those items you would love to keep aside for a good couple of days.(You will wonder you will not need them in future).
Now when the room is at least livable do your bed. And remember to make your bed everytime you use it.
If time permits you can mop your room which will make you feel heavenly.