I went to a figure drawing session this week. I used a pen and made myself stop sketching and just draw one clean line. It’s like jumping off a cliff. You have to just do it and pay close attention to space.
Also, this is the first time I’ve gone to a figure drawing class where the model was clothed. Wow, it’s so much easier! Clothes are like a cheat sheet for the body. “Ooh, the swimsuit straps are halfway down so that puts the shoulder there and the elbow there….”