For something on the semi-casual side, you can go for a double breasted blazer and a white and navy crew-neck t-shirt. Rounding off with black suede derby shoes is the most effective way to introduce a little flair to your look. As you're maturing from a kid to a teenage boy, you probably want to look a little older than your age. If that's the case, ensembles like this prove useful as a source of inspiration.