A white flannel long sleeve shirt and a white flannel long sleeve shirt are a pairing that every dapper man should have in his casual arsenal. Puzzled as to how to finish this ensemble? Rock a pair of tan suede derby shoes to amp it up. As you're going from your 20s to your 30s, you probably want to start dressing more like a mature gentleman. If that's the case, combos like this are ideal as inspiration.