Hi, I enjoyed looking at your gesture drawings. Your lines are drawn confidently that will help with adding line weight. Try concentrating on highlights and shadows at first. It helps me to put in one light source and give some thought to reflected light. I started drawing over my gesture drawings with brush pens and fineliners mainly to improve my confidence and line placement. (ghosting really helps) Drawing with graphite and erasing a little or using an H2 pencil will make it easier. This improved my use of line weight and placement quiickly. The best tips I can give is you don't need lines to connect everywhere, especially on highlighted c curves like the shoulder, use line taper to your advantage and less is more sometimes.
Line weight can also be used to create the illusion of depth. Thicker lines will look closer and thiner lines will appear to be in the distance. Another use for line weight is to give seperation to bone and meatier parts of the body, for example use a thin line for the elbow, and a thicker line going toward the wrist and thin again at the wrist.
The things that helped me drawing hands was to change from cylinders to 3d rectangles for the fingers and draw very large hands.
I got a little off track this is suppose to be a critque. When your adding line weight pay attention to your line placement. You're going next to your line not over it. Ghosting may help with your accurracy. Hope this helps.
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