If the situation calls for a polished yet neat getup, you can rock a navy double breasted blazer and black jeans. For an on-trend hi/low mix, introduce white low top sneakers to this outfit. A vivid example for any guy who's still working out how to dress after 30.
Pair a yellow overcoat with black jeans to feel invincible and look laid-back and cool. Tone down the classiness of your ensemble by finishing off with white low top sneakers. As you turn 30, you want to start dressing like a grown man. In this case, outfits like this are a tested option.