Go for a pared down yet casually stylish option by opting for a navy shirt jacket and jeans. For something more on the daring side to round off your ensemble, introduce a pair of beige suede sandals to the equation. So if it's a roasting hot afternoon and you want to look seriously stylish without putting in too much work, this look will do the job in seconds time. Overall, a good example of relaxed casual fashion for 30-year-old guys.