Althought I can't really show you anything to prove it, I start my Freehands with a very sharp pencil.
I'll just layout the Freehand as you would on a drawing. And if you want to test you can try diffrent shapes and Drawings on paper before you start drawing on your figure.
As you normally need a bit of space for that, it won't work on every figure. But even as small as
SM shoulder pads will work. As for Magnus, I don't have the figure, but clothing will work, depending on the amount of Folds in it and how deep they are.
Then, after you applied the pencil you can go on and Outline the Drawing with you smallest brush and ,depending on the colour, with a very thin black.
After that you can start applying colours etc.
This may help you aswell (Good old Duncan

) as he goes over the basics of Freehanding:
https://www.youtube.com/watch?v=RyPsQ_mJgEA&t=12s
Hope it helped