first you learn anatomy, gesture and construction. And i mean really learn it, I'm talking about learning 5 different approaches and studying other artists on these topics everyday for 3 months. fill a sketch page.
then you start using reference. and my friend, you are going to reference like a madman. make frankenstein ideas, take the pose from a random picture, the clothing and theme from a random drawing, take the lighting from a random movie scene and try to come up with a original idea mashing up these things. make it yours
let yourself be inspired by random things and rationalize it, don't inhibit yourself, allow yourself to be playful with your creativity and explore all angles to solve a creative problem. what's the worse that could happen?