How do i get back at my enmey?

hi i hav an enmey at school i really hate were both in grade 7 and in science we have to sit together up against the wall!! she is very annoying and complains about everything like... ur papers r on my desk get them off ur fingres r ugly u suk at volleyball ur braindead your a loser to her friends about me ) plez hlep my friend made fun of her once but ntohing really because there sorta friends well not!!!!!!!!!!!!!!!!its just that she dont hate my friends but there not her friends