Teaming a double breasted blazer and black sweatpants is a guaranteed way to infuse your current rotation with some effortless sophistication. Let your sartorial sensibilities truly shine by completing this ensemble with a pair of white low top sneakers. There are a myriad of ways to look cool and survive the heatwave, and that's one of them. When it comes to casual dressing ideas for 30-something gentlemen, this outfit is a good look on almost any man.