Inverted copy
copy the line drawing of the model once normally, then turn the line drawing upside down and copy it again
Plain paper is best when copying.
Ruled lines will interfere with recognition.
Image search
as an efficient way to know what you like
Materials are absolutely necessary.
It is a big mistake for amateurs to make them by karate.
Since there is no accumulation of materials, the poorly made work in front of them becomes the object of observation and input.
The work-in-progress is a canvas, an output, not an object of observation or input.
However, we need to look at the figures when we consider improvement.
That is another story.
The source of input is necessary.
Even professionals accumulate data, and for amateurs, data is even more important.