This smart casual combination of a navy waistcoat and white jeans is extremely easy to throw together without a second thought, helping you look awesome and ready for anything without spending too much time combing through your wardrobe. Inject your look with a sense of polish by slipping into brown leather loafers. As you're transitioning from your 20s to your 30s, you probably want to start dressing with more sophistication. In this case, inspiration like this comes in handy.