This pairing of a blazer and a white dress shirt is a tested option when you need to look classy and extra sharp. Take this look down a less formal path by slipping into brown leather low top sneakers. During the winter months, when warmth is the priority, it can be easy to settle for a less-than-stylish look in the name of practicality. But this look is a striking example that you can actually stay cozy and remain equally stylish in the winter months. When it comes to casual fashion tips for 30-year-old gents, this combination is perfect.