A navy denim shirt jacket and olive chinos? This menswear style will make women go weak in the knees. Dark brown leather casual boots are a good option to finish your ensemble. Can you see how very easy it is to look seriously stylish and stay toasty when colder weather hits, thanks to this look? So if you're on the lookout for a stylish yet age-appropriate pairing for a 20-year-old guy, this one fits the task well.