If you're a boy you wear hats if you're a girl that's fine too knit caps and snap backs are the best kind to wear
Shirt. Get a comfortable shirt logo or no logo. v-necks are a very cool style of t-shirt for boys and girls.
Pants. Skinny Jeans are the newest fad around well everywhere because they make anyone look awesome. Jeggings for girls. Bermuda shirts in the summer for boys and girls.
Shoes. High Tops are the style of shoes that make you look like a rockstar get shoes from brands like Nike and Adidas. Flip Flops are good at the beach and in the summer I prefer wearing faded glory those have pretty cool styles.
Don't wear jeans like flares that's not the fashion anymore.
If you follow all of these steps you are gonna dress for success.
Tips
Don't wear these clothes if you think they are uncomfortable don't wear anything you don't want to you can wear what you want to wear.
Just be yourself you don't have to dress cool to be cool your personality is what really matters not how you look not what you wear but your personality.
Warnings
When you dress cool don't be a jerk and be mean to everyone because you look cool. Sure you look awesome but, it doesn't mean you need to make anyone feel bad about themselves.