If the occasion calls for a polished yet cool outfit, you can go for a yellow crew-neck sweater and a blue chambray dress shirt. For a sleeker touch, add a pair of dark brown leather tassel loafers to this ensemble. When temps are dropping and autumn is setting in, you'll appreciate how perfect this look is for awkward transition weather. As you head into your 30s, you probably want to start dressing like a grown-up. If that's the case, combinations like this are a life saver.