Hi!
I'm really out of practice myself, but the best tip I can give is just to keep drawing them. Look at photos from different perspectives and try to copy them. Draw other things you see sitting around, too! I think one of the harder things is to learn to draw what you see and not what you *think* you see.
Also break down what you see into basic shapes, too, and practice drawing those. That will help you learn how to draw things from your imagination, too.
I've adopted Kasatka in the past, too!