Girls: any ideas about how to punk this dress up a little?

Blueswan • A smart busy feminist who writes, sews, cooks, etc. Bi/pan, kundalini/Sikh follower, and hopefully successful college student.
I love it and it looks good, but I want to tone down the 'girliness' a tiny bit. Normally, I would use a guys belt, but the waist detail rules that out.