Just to get you started, I think find a large piece of art to replace the mirror. Hopefully some of the pros will chime in for other advice. The curtains kind of disappear to me, and light seems a little small but could be the angle. I'm not a pro though. Pretty space to start with though!

You have a blank slate here. What colors do you like? I think Kulrn is right. Find a piece of art you like and then start pulling colors from that for the room. (Curtains, area rug, etc). The mirror is too small for that space.

It appears you are trying to stay neutral. Here are a couple of ideas on how adding texture and subtle color additions can help.