If you don’t have the foundation, buy Ben Berryman’s book first
It talks about a lot of human body structure, proportions, and perspective
You can copy it After a while, only by understanding the structure can you draw good sketches
You already know the structure well enough to sketch by yourself, then start practicing lines
It is recommended that you buy some sketches by masters and copy them. Yes, Western sketches are quite good and very vivid
Or some domestic masters such as Sun Li are very good at drawing. You can buy their sketch books to copy and practice lines
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