Upscale casual is a semi-formal style that mixes upscale pieces with comfortable, more casual pieces, like jeans with a V-neck shirt and blazer for men or skinny-leg khakis, heels, and a nice blouse for women. To look upscale casual, you have to avoid some clothes as much as you wear others.
Men shouldn’t wear T-shirts alone or shoes with rubber soles to an upscale casual event, but they can wear dark jeans or pants, collared shirts, and blazers. No one ever wears flip-flops to a fancy event. Black pants and little black dresses are great upscale casual basics for women. You can dress them up with jewellery and heels or down with flats.