Whenever drawing I always use reference photos. Personally, I'm not as advanced as far as drawing from memory but you'll be surprised what you can make just going off what you see and actually applying to paper. That's my method!! There are many body figures on Pinterest to practice, learn how to draw fabric by just look where the shadows are, and another good method is drawing boxes but in different perspectives which makes it easier to draw faces and bodies down the road.
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Another good this is what I call a shadow method where you start with a rough sketch/shadow of the figure and erase and draw again to make it more detailed, or do the same digitally with layers
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