act responsible so they will think that your mature enough to handle another pet. do chores without your parents telling you to do so. And act very mature . you can even try to borrow a pet or if you prefer a guinea pig to prove them that you can really take of the guinea pig or the pet. when i did that my parents said i can get two. but all i wanted was one! see you should try it . it worked for me it should work for you too!!!
AND DON'T STOP UNTIL YOU GET ONE!!!!