I’m not a fan of Halloween, but this is right up my alley.
I’d pick a costume within a costume, rather than designing something that reflects my innermost self. (This is at least 83% due to the fact that I have the artistic ability of a broken lamppost)
The costume would be this: Clothes, fairly plain, maybe jeans and a cute top. Please forgive vagueness, I don’t speak fashion. Or a casual dress. Ideally there would be boots of some description, preferably the kind with a wickedly tall, wickedly skinny heel.
To accessorize: a bag, a tote, maybe. The kind that I can just drop on the ground at a moment’s thought. It would be in a bold colour, against neutral clothes. Some of my favourite outfits are a bright pink bag against gray and black clothes. I’d add on a coffee cup of some description – either a takeaway one or a thermos, I don’t care – and the rest can be hidden in the bag for you to guess at.
OK, it’s not the most daring or vivid or wild, but what does a writer look like?