Drawing principles is not easy. There are so many to balance at once. I ask students to copy good drawings from old cartoons or from good comics just to see how pro artists use principles.
The next step is for the student to try drawing those characters in their own poses to see if they can apply those principles themselves.
Here, Geneva tried her hand at doing some poses of Tom. My critique was that they were good construction but didn't have clear silhouettes.I said to use negative spaces to make the poses read better and she redid them like this:
Now they are much better because you can read them more clearly. So construction is very important, but it is just step 1 to being able to control your posing.
See how Harvey Eisenberg does it:
This cover is a masterfully controlled collection of drawing principles all in perfect balance and clarity. Everything is solidly constructed and there are negative spaces separating each visual element - making them all read at once.