A white and blue gingham long sleeve shirt and navy jeans are a cool outfit formula to keep in your menswear arsenal. If you don't know how to finish, introduce a pair of tan leather low top sneakers to your ensemble. As you can see here, it's very easy to look sharp and stay comfy when cooler weather hits, thanks to this look. This ensemble shows how to keep killing in the casual style department as a 40-year-old.