I think one of the biggest things that helped me when I was learning to draw, was to draw geometric shapes like cubes, cylinders, spheres, and so forth. That helped me to learn about perspective, basic shading and lighting, as well as learn to control my strokes better. (though I didn't know it at the time. I just drew the shapes 'cause I thought they looked cool.)
Another thing is to look at real references. Things in real life if you can, but if not, at least look at photos/videos of the real thing rather than looking only at pictures drawn be other artists. In case of drawing anthros, which don't really exist, you'll instead have to look at real people and learn about anatomy, and also look at foxes (or whatever species you are making). Human anatomy, and animal anatomy books can help here.
And of course the biggest thing: practice!