Hi, pay attention to the negative space between the two legs, and you will spot all the differences. Also i saw a Prokos video yesterday, about: how to give feedback to yourself right away, in order to spot all the line deviations. https://www.youtube.com/watch?v=1J7RQvKnWf4&t=21s and in case you don't have a computer, you may print the image that you want to draw in the exact same size, draw it using the same proportion 1:1 and use it as a comparison guide afterwards when you want to check for any mistakes, using a ruler, a grid, etc..

Hello, To answer your first question: The highlights you applied to the image already are more than sufficient IMO. But if you were to do this pose again, I would omit the highlights and stick with 3 - 5 tones. Specifically starting with your average light and average dark first then blending out your edges from there. The picture of the figure actually has barely if any true highlights anyway. To your second question: The foreshortening I see in your sketch is mainly coming from the legs and the upper back, giving the glutes and lower back more emphasis. I have done this too when I have focused too much on one part of the drawing in the beginning just to be surprised at the end where the focus point is bigger than the rest of the features. This is also common when drawing from 2D reference as your eyes are not judging true distance between you and the model. The answer here is to establish a baseline first then check your work as you go. For instance, I would establish the distance between the sides, top and bottom of the reference (do this by your eye without measuring). Then after establishing the baseline create a rough sketch of the silhouette. Once you have the basic big shape done, then go back and measure your distances and adjust accordingly. The process of deconstructing and analysis through measuring will help solidify your knowledge. Hope this helps a little.