For a casual and cool look, pair a black blazer with grey jeans — these two items go perfectly well together. Introduce a pair of slip-on sneakers to the equation to effortlessly step up the appeal of your look. When it comes to dressing for fall, nothing beats a cool ensemble that will keep you comfortable and looking your best. Gents wondering how to pull off cool off-duty outfits as you turn 30, you have your answer.