Why not consider wearing a white and navy vertical striped long sleeve shirt and navy sweatpants? These two pieces are very comfortable and will look awesome paired together. Introduce a pair of navy canvas slip-on sneakers to your outfit for an extra touch of style. So when summer is over and fall is in the air, you'll find this look to be your everything. Relaxed ensembles for stylish 30-year-old men aren't actually that hard, as you can see here.