Hips one more time, because they are important. 

Take a walk in front of mirror and look at the movement of your hips. Have so much importance on your hip so that movement can happen. This is because the hip start and drive the movement and this make a huge difference between a good animation and a bad animation. When we stand, our weight is never centered between the legs. For this reason, we shift to one leg or the other to distribute the weight. When you do it, it forces the hip to make an angle up on the leg that is taking the mass of your body. 

"And why I don't fall?"

Because your Center of Gravity. Remember: all body is pulled to the center of the  Earth, because the Earth's mass is greater. Otherwise, if we jump off, would leave the Earth orbit. Therefore, Center of Gravity  is the point where you can balance all these forces of attraction.  

To simplify finding your center of mass, you can draw a line from the neck down to the heel of the supporting foot and you can see if your pose is working or not. 

"Okay. But what if my pose is extravagant?"

Well, always remember your hip is driving and starting the movement. Give attention to it to make your pose works. Let me show an example. 

Look what she did with the arm to balance the body. And look how the body is distributed between the center of mass. 

"I can break the rules?"

Yes, you can. In animation, we have freedom to exaggerate but, as always, know dosing and where you will do it. You can break the rules, but if you ever do it, lose the believability