>>37808706As you are doing this on paper, I suggest you start with a pencil and trace a skeleton (just a basic collection of circles, spheres and lines) with a pencil very softly so you can have an idea on how to put the definitive lines on it. Then, when you've finished inking, just erase them and proceed to paint.
At least that's what suits me, experiment and find the method you feel more comfortable on.