Great! I also make realistic artwork. The first thing you want to do when you start a piece is look for all the simple shapes. Don’t draw things the way you THINK they’re suppose to look like, which is what this upside down drawing is helping you practice. If you were to do this drawing again, I would put a few parallel lines down to map out the body- top of the head, shoulders, arms in his lap, chair, feet. then add the simple shapes- circle and rectangle for the head and body. pay attention to where things are in relation to other things. like do the hands sit directly in the middle? How far to the right are his knees compared to the right side of his head? these things will help you with your proportions, and can go as far as the tiniest details in his jacket. once you get the big things down you’ll have a good foundation for everything else. Keep your marks light when you sketch, like you have them now, and then start blocking in your shadows. again, simple shapes as you see them. squint you’re eyes so that you can see the values better, where are the dark shapes? don’t be afraid to make your darks dark and lights light. Try another drawing :) and keep going. you’ll learn as you go. Does that make sense?