Interesting work..you have the right idea...might I suggest you
get some magazines and or comic books to see comparisons between
"real life" forms and drawn ones. If you can afford it..investing in
a beginner book for comic drawing would help show you how to transform
your more blocky characters into more curvy ones with greater dimensions. This will help your creations to have a more life like appearance. The below book is excellent because it has an extensive section on the more cartoony oriented types of drawing such as
Batman TAS.