One of the things that you can do, if you feel so inclined, is to offset wide shoulders by bringing focus away from them through your clothes, hair or accesories. Dark colors at top, brights at the bottom, v-necks, long necklaces or even having you hair fall over your shoulders can do a lot to take attention away from the shoulders.
But like others have said, passing is a whole package deal. The more cues you give as female the less you have to worry about when it comes to things that are harder to change. I have a friend who looks female, no doubt, but her mannerisms, how she communicates, etc, seem to get her gendered male sometimes.