learn basic colour theory. There are a lot of good tutorials on deviantart. This is also useful for sig design.
Speedpaints are great. I learn quite a bit from them.
Learn basic anatomy too. Like I dunno bout dragons, but unless you're trying to draw titans, then learn basic proportions.
If you do digital art, get a good enough programme. I'd recommend starting with MS Paint then sumopaint.com then maybe GIMP or MediBang, if you have no money. But if you can pay, then I thiiiiink Photoshop and/or Paint Tool Sai are good?
Learn to colour, if you do traditional art. Unless you only do black and white sketches.
Learn to shade. This is important.
If you do digital art, DON'T rely on the airbrush for shading, you can use it for smooth shiny plastic objects or whatever, but DON'T use it for absolutely everything! It looks all blurry and unclean....
Um. There's definitely other stuff. But I can't think of them right now....