the only resources you need are a pencil and paper
just draw what you find interesting from different perspectives
try to rely on yourself to improve each drawing
what do YOU find wrong with it?
how can YOU remedy it?
ultimately this will lead to artwork that is YOU, which is what art is about.

the time it will take to reach a point YOU believe to be good depends on you inherent talent and actual desire.
from your post i would guess about 7yrs to never.