It looks fine to me, but one always seeks to improve :D Good luck~ ('specially with the tatami >x<)

Oh, I see... I use refillable fine markers (not sure of the name; first language is not English xD) like these (https://www.penfountain.co.uk/images/Staedtler%20Graphic.jpg). Had to buy them for a course at uni, but never again used them =="
I'll need to trace my pics to a better quality paper before inking OTL