Before you find your art style or even start anything, start studying anatomy so you know how the human body is structured/built. Afterwards you´ve done that, I would recommend you studying colors and shading. There´s plenty of YT videos on that topic.
Then, if you´re not going for realistic portraits like the things they teach you in art school, find your art style.
with my drawings I always do the details after done with the outline of the drawing. I also enhance the drawing by traceing the drawing in pen after the details
Regarding the anatomy of an arch, what is the springing line? The springing line is an imaginary line between where the curves of the arch begin on each side
