yep thats really the best "solution" its just possible over time and practise of course there is a "base" talent that helps to speed up time a bit
for a dull untalented block like me is even a 1 year everyday 7 hours drawing class not enough to draw a simple a straight line (ok im a bit exerggerating but its pretty close

)(and i drawed in my free times too)
so i just quit someday...
but you have a good hand as i can see it you just need some theoritical lessons about light and shadow and little practise. you will see after a year "living" with a sketchbook
you will laugh at your drawings now