Go for a simple but at the same time cool and casual choice in a white crew-neck t-shirt and jeans. For something more on the dressier end to finish off this ensemble, introduce a pair of burgundy derby shoes to the equation. Ideal if you're scouting for some incredibly inspiring style for gentlemen in their thirties.
If it's comfort and functionality that you're seeking in menswear, wear a black crew-neck t-shirt and jeans. Don't know how to finish this look? Finish off with a pair of burgundy derby shoes to up the classy factor. As a 30-something Millennial gentleman, you probably want to start dressing maturely. If that's the case, outfits like this are a tested option.