Before I started my comic, I made a Pinterest board for the fashion each character wears, so I always have inspiration and reference and a personal guideline for your the characters dress. And even though it's all fairly casual fashion, each character has a distinct style and certain items of clothing or accessories that only that character will wear.
So the main character Skyler will wear straight-leg jeans (usually with rips or patches) and red Converse sneakers. He doesn't wear plain t-shirts, his shirts are all either Henleys or ringers or baseball tees, and because it's fall he'll usually layer up shirts with long sleeves or a hoodie.
Paige always wears either skirts or shorts, with leggings when it's cold, and cute sweaters or blazers. She wears black boots, and likes chunky scarves and socks. And she always wears her hair in a different style, because she thinks it's fun and cute.
Levi almost exclusively wears sweaters, specifically ugly Grandpa sweaters in tacky patterns and weird colors. He will layer it over a v-neck shirt or a button-up, but never wears ties or anything. He prefers skinny jeans and brown dress boots.
With those rules in place for myself, it's actually really easy to come up with clothes for them to wear. And each character has an associated color (Skyler wears red, Levi wears blue, and Paige wears pink and purple) that carries over most of their outfits for visual consistency, but it also means that I can dress Skyler in blue and Levi in red when they're thinking of each other, and that visual cue is pretty apparent.
