Studying to get better at anatomy

Well, for example, the line from knee to hip is one slightly curved line. You weren't sure about the curvature, so you drew a short line, then corrected the curvature and added another short line, and so on. This will always be visible in the result, and will look insecure.

There is the idea of "line quality", to try to use long, determined lines. It is related to "line economy", the idea to use as few lines as possible to communicate.

If you look at a drawing and immediately have the impression: "Oh, that looks very clean and professional", you will often find, that it is drawn with very few lines.

To achieve such a result, there are several steps of training.

a) you need to practice to actually draw long lines. You have learned using a pen by learning to write, but when you are writing, you are only using your fingertips and your wrist to direct the pencil. If you want to be able to draw long lines, you will actually have to practice to draw from your elbow and even your shoulder.

Practice drawing long straight lines, with a determined start and end, without a ruler. Practice drawing parallels. Practice drawing curves, with a controlled curvature.

You can check out drawabox.com to find some good ideas for training.

b) You need to learn to find the simple, big long lines in your reference. As beginners, we usually try to draw one detail, then add the next detail, and so on. Before the drawing is finished we change the scale of each detail a bit, and suddenly the relations between all our tiny pretty details no longer match.

Those quick studies, that this site offers, 1 minute, 30 secs, etc,.. are meant to force you into using as few lines as possible to portray the entire pose. That way you start out each drawing with a sound structure, which you then can later embellish with details, instead of trying to assemble the image out of a puzzle of details, that you can only hope, that they will fit together at the end.