This casual combo of a white crew-neck t-shirt and a dark green polo comes in handy when you need to look dapper in a flash. Go the extra mile and switch up your ensemble by sporting a pair of dark brown suede derby shoes. So when summer is fading away and fall is taking over, this look has a good chance of becoming your go-to. Your thirties is the decade to start dressing with more class. And it's easy with examples like this.