I feel like you should have a base sketch and learn how to simplify the human form to it's bare essential, it feels like you're trying to draw the image directly, (including the clothes etc...) but the final result ends in a slightly messy drawing.
As long as you don't try to force your pencil to be one with your paper, it's easy to erase the sketch.

Building a visual library also helps with that. The mind's eye is helpful but it's unreliable without a concrete domain of images to reference from.