Oooh Moni that last one is awesome! To me, it is all about the spirit of the piece, if it gets your emotions going then it is really a work of art. If you work with love, I think the technique and skills just fall into place.
I have been drawing since I was like 3 or 4 years old, and I have always pretty much done nothing but dogs and horses. Really. Don't ask me to draw a tree or a building or a person, I can't do it. It took me a long time to get the hang of cats. But a dog or a horse (or a unicorn, heh heh) I can do. I am very limited! But that's ok with me! I never took specialized classes unless you count art lessons when I was 5 years old and just the normal classes in high school. I'm "self-taught". I practiced and practiced. I am still practicing. There is always room to get better as long as you want to. I think if you keep up with it you can really make some beautiful art.
Shading you can get a lot of hints from books. Just flip through some drawing books and find some pencil drawings you like. Try to draw it just like you see it in the book. That is great practice.
Senghe, nice sharpei! Those are hard with all those wrinkles trying to make them actually look like a dog instead of a bunch of random lines!
Felicity- that's awesome you are doing 5 portraits for the same lady!! I have one client who has 15 dogs and she practically has a gallery of my work in her hallway! It's so fun!
(here's my latest creation)