Anyone can be good at art, all it takes is time and patience. The only reason I can do this is because I took art at GCSE. Even then I couldn't draw for squat. Only in the last few months, leading up to the exam, did I begin to be able to draw (so to speak). Like any skill it takes practice If you want proof look at your own gallery, your second twi sketch is an improvement over your first one.
Right so the shading... It's just, shading you know? Smudging and stuff, you know how to smudge? I used 3H for sketching it out, as in drawing the guidelines and then the face and mane. Used a rubber to rub out all the lines outside of the face that I didn't need. You can keep in the guidelines inside the face as the shading covers them. Next I used a 2B to go over the lines and make them stand out. I then done the mane and then the eyes. Then I just used the excess pencil that you always get on you hands whilst drawing stuff such as this to begin to smudge. I smudge the pencil in the direction that it should be going. That's about it really, I use cartilage paper which does help, as the good quality keeps the picture crisp. If you want a real tutorial I could make one sometime.