Human anatomy is, for sure, one of the hardest things to draw. But at the same time it's one of the most interesting things to draw, because... hey... we love making characters, and it's nice if they at least look a bit like a human being. I'm still far from perfect at drawing the human body, yet I've accumulated some very useful tips, tricks and websites.
Drawing from life
Drawing from life is awesome!
Look for life drawing classes in your environment, or if they're not available; ask your friends to pose for you. Go have a drink in the city when the weather is nice, and sketch people passing by. There's nowhere you learn more about human anatomy than by observing and sketching real people. There's only one downside to this; dynamic poses are tricky, as it's hard for any model to hold a difficult pose for a long time.
And no... drawing (nearly) naked people in a drawing class isn't awkward. I