For dapper style with a modernized spin, dress in a navy long sleeve shirt and black wool dress pants. After 30, you want to start dressing maturely. If that's the case, inspiration like this comes in handy.
Navy Long Sleeve Shirt with Black Wool Dress Pants Outfits For Men In Their 30s
This is definitive proof that a navy long sleeve shirt and black wool dress pants are awesome when combined together in a refined look for a modern man. Ensembles like this go a long way towards developing your style as a 30-something Millennial guy.