Look casual and cool without exerting much effort by opting for a white vertical striped crew-neck t-shirt and brown chinos. Our favorite of a myriad of ways to finish this outfit is with a pair of beige athletic shoes. So if it's a summer day and you want to look dapper without exerting much effort, this getup will do the job in no time. All in all, an ideal demonstration of off-duty style for 30-year-old gentlemen.