Sometimes you just don't know what to wear. Of course you could buy some new clothes (not so environment-minded) or you could take a look in your boyfriends (or your dads) cupboard! Besides, you save a lot of money and maybe even frustration if you can't find something special. Just use some accessories like a belt, a statement necklace or your favourite high heels or brogues. It will make you look more feminine but powerful at the same time.
Here some snapshots for more inspiration:
I hope you'll be inspired! Have a nice day!