When we sketch for ourselves, it's fine if we sometimes make things a little unclear or messy, as long as we know what we have to put there when we do the lines later. We have the full idea in our heads, after all.
But this is not a personal sketch, it's a sketch you're sending to someone else to work on.
As such, please make the sketch clearer because i can't distinguish the shapes well. I shouldn't be making assumptions or filling in gaps in the image, it has to be 100% clear for me to use as a basis for lining over.
Edit: you can look at the first collab thread to see the sketches people sent each other. Or do a quick Google search about how pencils and inks work in comics
for example
