I'm a tomboy and what I wear are tshirt, sweatpants/joggers, shorts, sweatshirts and slides or sneakers. That's all I own. I like to wear comfortable clothes. The sport I play wants us to dress up on game days at school for some reason. So what do you suggest?
You have nice black and grey jeans. T-shirts exist in more fancy variations than just plain and sweaters like stuff even exist in more fashionable variations. There are very fashionable sneaker like shoes and a sporty jacket may complete the whole. A simple dress up, but nice to wear at other occasions too.