Effortlessly blurring the line between sharp and laid-back, this combo of a crew-neck t-shirt and navy chinos will likely become one of your favorites. If in doubt as to what to wear when it comes to footwear, complement this getup with a pair of navy slip-on sneakers. As you're going from your 20s to your 30s, you want to start dressing more maturely. In this case, combinations like this are a winning option.