Demonstrate that nobody does semi-casual menswear quite like you do in a charcoal lightweight puffer jacket and navy chinos. For something more on the daring side to finish off this look, add white and green leather low top sneakers to this ensemble. So as you can see, this outfit is a really great choice, especially for unpredictable fall weather, when the temps are falling. This ensemble illustrates how to succeed in casual dressing as a 20-year-old gentleman.