Girls only i need tips on how to be more feminine?

Ok so i am a guy and i am gonna cosplay or dress up as 2 female characters and i want make up tips ways to move sit and stand And the most important and weird i want to know how to make it so i have a bigger chest i don't want to stuff my shirt or wear a padded bra i don't mind if it is permanent i am flat and want to make it so no one can tell i am a guy i already have a longer neck and arched shoulders and smile down any tip is appreciated help please