For an ensemble that's worthy of a modern fashionable gent and casually classic, consider wearing a black leather biker jacket and grey dress pants. The whole look comes together wonderfully if you add a pair of black leather chelsea boots to the equation. Wear this getup to achieve a more mature look as a younger guy.
Loving how this pairing of a camel overcoat and grey dress pants instantly makes any gent look stylish and sophisticated. For something more on the casually edgy end to finish off your ensemble, introduce black leather chelsea boots to the equation. If you're 20, take inspiration from looks like this to take a more serious approach to your style.