As a crossplayer here are a few tips most have already said.
Learn to do basic make up from a friend, the photos turn out better. Make sure the make up matches your skin tone and costume. Make sure you shave, chest, armpits, face/neck and legs (though if yo have leggings or tall boots you can cheat here a bit). Practice a female voice if you want to use one.
Speaking from experience here, if anyone gives you crap for doing this and you enjoy doing it, simple wave your hair back and smirk. "You're just mad cause I make this look good." I stole this from above, but honestly 100% this. If people give me a hard time I mess with them by giving them a response they won't expect. But having fun is the main key. :)