Also, for more dynamic poses. Use a curved line connected to your head to any place you wish because that will be your spine almost. Here is another example on my older drawing.

The thing I learned is the head size measurement for human anatomy. Also think of body part like things that exist. Like a hand is gonna start like a baseball glove or mittens. Etc.
(I couldn't find the ones I had, but found these examples on google). Also, use yourself/firends for reference.