Marrying a brown waistcoat and a dress shirt is a fail-safe way to infuse your closet with some masculine refinement. Dark brown suede double monks are a surefire way to give a touch of stylish casualness to your outfit. This combination is a pretty savvy pick, especially for fall, when the mercury is starting to drop. As a 20-year-old sliding into your 30s, this is how you dress as an adult.