>>3 Seconding CoffeeCream's advice. If you observe people or things long enough, you will be able to recreate an image of them in your mind after a while. As for poses, I pin them down by drawing stick figures with circles for joints when I'm watching people. This way, you will get a better understanding of how the human body moves and how your point of view/ angle affects what you see. If you're missing some poses, you can also use your own body for reference.