Bump up the sprezzatura factor in a navy blazer and white jeans. Wondering how to round off your outfit? Round off with a pair of black leather derby shoes to spruce it up. This getup is a viable option if you're piecing together a kick-ass ensemble that will take you from summer to fall. As you head into your 30s, you want to start dressing like an adult. If that's the case, inspiration like this comes in handy.