I've been drawing for a few years now. I'm making some money from commisons ,not aiming to go full pro(at least for now) .Made the big mistake to start from copying anime.I was stuck for awhile drawing total crap . Went to some life drawing classes , my stuff got slightly better,Then i was a neet for a year and decided to really level up and got a copy of scott robertson's books .They helped me boost my art skills in a very short time by like 200% , i'm not even joking .Understanding the theory behing stuff and doing some practice is gonna be much better than drawing 10000 crappy sketches. Another tips is to learn some basic 3d ,mostly to use for lighting/perspective reference when painting or even overpainting if there is a lot of perspective .Also i feel that people don't emphasize how much planning you should do for a finished piece. Reference , thumbnailing , design choice , color and lighting choice , the more you plan the better.Using photos as textures is also fine , as long as you do it nicely .(Eytan Zana is a good example).