What is it you want to improve first? Asking how to improve is a rather broad brush stroke, so it's hard for others to pin-point where to start ^_^

Yeah... you're right. I'm thinking basics, or anatomy. Maybe see if the local college still offers live model sessions.

Well that kinda helps, yeah. Anatomy books or even anatomy photos online help too.

https://www.google.com/search?q=back+muscles&biw=1920&bih=921&source=lnms&tbm=isch&sa=X&sqi=2&ved=0ahUKEwi3yJP0l8DPAhVV-mMKHUj-B3QQ_AUIBigB See all those colored boxes between the address bar and the images? All body part muscles. That's a huge anatomy saver. :)

Ditto.

I would say the best way to improve from your position, is to look at the fundamentals, the basics. There are 2 things that are important. The knowledge and memory. Knowledge is build by looking at shading, light, colour theory, anatomy and different techniques. Memory is builid by simply drawing a lot of different topics and materials. You can see some artists drawing cubes or spheres for example, and all of them with different materials, like grass, wood, metal, blood, and so on. Escentially, you want to reach a point, where you don't have to think anymore about the strokes and how a certain material works, so you can spend more time on your designs. It's kinda like sport I guess, you can't do the exciting stuff if you don't work on your stamina first, because playing in a 20-30 min match doesn't do you any good if you can't even run for 30 sec. Referencees are also a very important part, there is no great artist that isn't using SOME references, be it for posture or lighting or you name it.

You could also take a look on some artists like Bobby Chiu, who gives some interesting tips:
https://www.youtube.com/watch?v=u_4hZmZmNLw&feature=youtu.be

If you're more into digital Art, there is Feng Zhu and Scott Robertson or Noah Bradley, they all have youtube chanels where they talk alot about different ways to create art.

That makes perfect sense. I've seen some examples of that from Blizzard when they were developing Diablo 3. It was 3d, but the same idea, make a sphere with different materials. But... yeah... I need to go back to basic & material theory, as well as anatomy.

In terms of references, you're 100% right. I've tried to eschew references as much as possible, but there are times where I can't wrap my head around stuff. Hell... I try to pose myself in a mirror sometimes to see how things look and feel... which is awkward at times ^^;.

I can do either or, actually. I started on paper / pencil / pilot pen, then moved to the computer. I'll look into those guys when I have some spare time... adulting sucks x.x.

Thank you for the advice!

I am glad that I could be of some help :)!
Well, the great thing with art is that you can pretty much learn everything on your own, there are so many great books and materials around, like for anatomy or simply studying shadows and just practise, practise and more practise :D. That's the beauty of it. No reason to spend a whole lot of money on fancy courses where you will do all the stuff that you could do at home anyway, like drawing animals, or texture or what ever. The only thing that you can't really learn from home, is someone with knowledge and experience looking at your work, but this is I think really only important when you're trying to get on the details, spotting mistakes that you can't always see on your own. It can really help you when you have someone pushing you further and with years of experience giving you some advice. Also one aditional tip that I learned from some artists - like Feng Zhu, if you're doing work on your PC this should be pretty easy. Flipping your images! Like with a mirror. Once you worked a couple of hours on something, you become blind to mistakes and errors, but when you flip the image, you suddenly see a ton of errors! It really works! You should give it a try if you havn't already.