I agree with SizzyBubbles about not copying other peoples work, but a good drawing trick and excercise is to actualy trace artwork/pictures your trying to learn. I know your thinking " trace ? realy , im not 5 lol " but , by doing so it will help you understand the anatomy of the body and start to visualy see images in three dimentions like in real life. The best way to trace/practice is to have a makeshift light table like an annimator would use. all u need is a see through drawing surface ( a glass table/coffee table ) work great and have a light source shine underneath it ( a small lamp or large flashlight ) that way when you put your blank piece of paper over the other piece with the picture you want to copy the light makes both pieces transparent. Its a good idea to tape the 2 pieces together so there not sliding around making you loose your place. ( use tiny pieces so they dont ruin the paper ) Start trying to trace artwork of characters you already know and like , its easier because you already know what they look like in your head. Then when your comfortable start trying to copy/re draw them by just looking at them. But like these other guys said " Practice , practice , practice !! lol . Im 29 and have been drawing since i could pick up a pencil and still learning knew things all the time .