First I sketched some really messy redlines as a guideline for my lines. A lot of stuff wasn't added in the red lines, and were added in the final sketch. I used the marker brush from Medibang Paint Pro.
On a separate layer with the Pen Brush, I drew over my redlines but added some things to it. Notice how I don't completely follow the guidelines. Those are just a base sketch you could say.
Edited at September 9, 2018 02:57 PM by Valhallian