This casual pairing of a blazer and a white and navy polo is a lifesaver when you need to look cool and casual in a flash. If you need to instantly tone down your outfit with a pair of shoes, add a pair of white low top sneakers to your outfit. This here is hard proof that it is indeed possible to survive the scorching heat and look cool and fresh while doing so. And if we're talking casual style tips for 30-year-old men, this ensemble looks cool on most.