Busy off-duty days require a pared down yet cool and casual getup, such as a light blue denim shirt and sports shorts. Introduce tan slip-on sneakers to the mix to instantly boost the wow factor of your ensemble. So if it's a warm hot weather day and you want to look stylish without putting too much effort, this ensemble will do the job in no time flat. Those who are curious how to wear cool casual style as you turn 30, you have your answer.