Pair an olive shirt jacket with a grey tank to put together a casually stylish outfit. If you want to break out of the mold a little, add a pair of brown leather derby shoes to your ensemble. You can bet this getup is great when colder weather comes. As you're moving from your 20s to your 30s, you want to start dressing like a grown man. In this case, outfits like this are a never-failing option.