I remade half of this costume recently to make it photo-shoot worthy. Sailor Moon is one of my favorite animes but there's not enough dudes on that show!
It was really simple to make, all I did was follow a Sailor Fuku tutorial (Link below) and modify it to make it masculine. The design was from mostly looking at Sailor Moon's outfit and thinking, "Okay, what would I wear?". For example I didn't want to wear boots so I switched them out for converse, added cuff links instead of glove rolls and made her brooch into a belt buckle, making her trademark bow into a sash.
Lastly I made her moon healing wand into a katana to make the costume a bit more masculine, I didn't want to run around the convention with a silly wand haha. The circlet (or tiara -_-...) was made out of foam and wire so it adjusts to my head.