For an ensemble that's extremely easy but can be modified in a myriad of different ways, consider teaming a shawl cardigan with navy skinny jeans. To bring out a classy side of you, introduce brown derby shoes to the mix. So as you can see, this outfit is a really good pick, especially for transeasonal weather, when the mercury is starting to drop. Smart casual looks for stylish 20-something men aren't actually that hard.