Hmm, we have lots of suggestions, but how far do you want to go?
Questions:
Who sleeps there? Who uses it for an office? What other activities (

) are going on in there other than sleeping and the obvious.
Suggestion:
First remove everything that does not belong in there.
Use our Declutter 101 as a guideline (you can download it for free on our website) to get some order.
Paint and get either real curtains or some blinds.
Check second-hand stores for replacement furniture.
And then, of course, you could hire us to help with this dilemma.