Consider wearing a denim jacket and a grey long sleeve shirt to achieve an interesting and modern-looking casual outfit. Dark brown leather desert boots are a welcome companion to this ensemble. In the winter months, when warmth is above all, it can be easy to settle for a less-than-stylish getup. This getup, however, is a practical illustration that you can actually stay toasty and remain stylish at the same time in the winter months. And if we're talking casual dressing ideas for 30-year-old men, this getup is ideal.