There is plenty you can do to stop uniforms and you may find these suggestions will be taken more serrious then crying uniforms suck.
Come up with as many reasons as to why you don't want uniforms. They should be logical and just saying you don't like the way they look won't get you very far.
Write courteous and respectful letters to your school administration and PTA about your opinions.
Circulate a petition around your school to present to the administration and PTA
Get together with your friends for a letter writing party.
Talk to school counsel.
If they don't do anything, run for school counsel (no more puppet governments!)
Talk to your Parents, they may be on your side :-)
If they are on your side ask them to exhert their influence as a parent by going to PTA meetings and talking to administraion.