hey i would really advice you to use reference or have some kind of concept drawn out that way you will have a clear cut goal of what you want and wont waste so much time on guessing on where you want it to go I did a stick figure-like drawing (I'm horrible at drawing) for the basic shape before I started, but now I mostly google for ref images for the specific pieces I'm making at the time (like car batteries, pistons, rotating joints, etc.) to get inspiration.