Why not consider pairing a charcoal crew-neck t-shirt with blue jeans? Both items are super functional and look amazing matched together. If you're hesitant about how to finish off, a pair of black and white leather low top sneakers is a nice idea. All in all, a good example of off-duty style for 30-something gents.
Try pairing a charcoal crew-neck t-shirt with blue jeans if you wish to look casually cool without putting in too much time. Get a bit experimental on the shoe front and play down your getup by slipping into a pair of tan athletic shoes. This combo proves how gents in their thirties slay in the style department.