For a casual and cool outfit, pair a navy denim jacket with a white long sleeve shirt — these two pieces work perfectly well together. Our favorite of an infinite number of ways to complete this getup is with brown suede casual boots. If it's one of those dull autumn days, what better to cheer it up than a sharp look like this one? As a guy in his 30s, you want to start dressing like a grown-up. If that's the case, combos like this are ideal as inspiration.