If the setting permits a relaxed ensemble, you can easily dress in a dark green field jacket and blue jeans. Low top sneakers look right at home with this look. Casual getups for stylish gentlemen in their 30s aren't actually that hard, as you see here.
Team a dark green field jacket with grey jeans for a comfortable ensemble that's also pieced together nicely. On the footwear front, this ensemble is rounded off perfectly with low top sneakers. A no-brainer pairing appropriate for maturing gentlemen who like casual clothing.