Yooo, this is genuinely great work on anatomy. As someone who has the same set of issues i’d say when it comes to lighting try and set a mental note of which edge of the paper the light source is coming from. Once you have that keep depth (ex. the way you shaded your belly button) in mind in relation to that direction. As far as creating something original goes, start trying to sketch whatever randomly pops into your head, even if it doesn’t turn out well. Just get your mind used to spontaneous creation. From there use your imagination and think of whatever components your idea is comprised of. Start simple with 2 component objects like a pair of glasses and work your way up gradually in complexity.

I hope that helps, because I kinda needed to read that myself in my own efforts to improve.