Ok , I am not a professional animator , neither worked on the original show .
I am just posting this to help people to understand the basic on sketching a character .
You can see on the first image the basic lines , that gave the proportion and pose .
on the second , you add the volumes to start making it looking as the character .
And finaly you clean the lines , and add the details .
After that you still can add any other detail .
dress , gadgets, rivets , etc .
have fun .