Try starting with sketchnotes (visual notetaking) and go further from there. At first, simple items (human, cup, ...) without any visual depth will give you a f

Try starting with sketchnotes (visual notetaking) and go further from there. At first, simple items (human, cup, ...) without any visual depth will give you a feeling about proportions and general characteristics. From there, you can add details and eventual some depth.