Smile. Even though some women find it creepy when a man says they should smile, it really is good advice because smiles can be contagious. If you walk around and someone smiles at you, generally it lifts your spirits a little. Just as long as the stare isn't too long.
A stranger once told me to look up straight , never to back down or give in no matter the pressure or circumstances if my heart tells me I am doing the right thing, that advice just couldn't leave my mind ever since.