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.
wear clothes you like
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.
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.
You could dress up as a killer or a kid.
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
because is an adult that acts like a kid
Karate Kid
just dress up and be on tv