S.C.
My first born is a boy, my next is a girl. I used a lot of my son's clothes on my daughter in a way that people still knew she's a girl. For example, I put a pink or flowery, girly girl shirt with blue pants, or pink pants with a more gender neutral shirt. I did not put but one really boyish outfit on her, the one was just way cute and she looked sooo cute in it. But when I did, I put a flowery headband in her hair! NO on would think that she was a boy that way!
As for the neutral clothes, like another woman said, girly them up with ribbon or things like that. Put barrettes in her hair if she has any, or bonnets or headbands. Pink socks help too.
Congratulations on the new baby Girl!