Can't figure out how to cleanly match the style for this number design

I'm a beginner, and I have this design idea I am struggling with for some reason - like my brain won't visualize how to create the effect. I want to make like a lined art number 3 (eventually multiple numbers). I made an initial shape I want cleanly, but I am stuck on making the companion bits so that the whole thing is smooth/clean/cohesive. Will attach an image of the rough idea (red) and my shape (blue)