Hye p33p ,
Like you i have no formal art training behind me ( except self-education ) , I don't use grid and scan or others techniques, just draw on the canvas, but....
before directly directly draw, you can make some preparatory works like thumbnails, composition, big shapes , color research , and so on...
and i don't think there 's a sort of "hope" in drawing (painting) process , perhaps some accident but essentially more or less mastered ....
But don't hesitate to choose your OWN method :
- scan is cool if you are more confortable with a "real" pencil.
- grid is not copy , it is used to get the right proportions and positions..
These are only tools to achieve your goal : make a good paint , that's all.
Your Rosie the Riveter is well done.