there is no specific answer for this question. "popular kids" don't all dress the same way. You would have to give a specific "group" that you think is popular to be able to answer this question. It also depends on the time period.
To play baseball and Dress up like a cowboy
look like a dork or idot
Easy--Go with the flow. Do what populars do, dress like them, act like them, everything!
Wear a shirt that's too small, little shorts, and dirty sneakers.
The Spanish dress like the rest of the western world.
You could dress up as a killer or a kid.
Figure out what made them popular and be like that. Or find you have in common with them. Just tsaying, it won't be easy.
A lid dressed as a soldier should give commands like "attention" "right turn" in a fancy dress competition.
his not popular his only a normal kid well funny kid
just dress up and be on tv
Karate Kid
because is an adult that acts like a kid