Please please tell me how can I control my older sister's temper?

stand up to her. calmly tell her it is none of her business what you do. u asked and got permission so that is the end of the discussion and tune her out. tell her she is not your mother and she doesn't need to scream at you u r not deaf and can plainly hear her in normal tones. keep telling her to control herself and her temper. stay calm. if dad is near by ask him to come into the room that u can't calm your sister down and let him handle it. as for her room and her messes just keep pointing out she is no better at cleaning or whatever but above all else stay calm the louder she gets the quieter u need to be. remember u can not control her or anything she does. she has to want to control herself. throw things at her like how do u ever expect to find a husband screeching like that? don't change her words, give them back to her. make them her fault. your room is a mess = yours is no better. did u wreck the hard drive = u lost the usb cord. change your temper patterns. let her worry about hers. when she sees she can't ruffle u and get a fight she will stop trying. it will take a while but it will teach u how to handle yourself outside in the real world when u r ready for a job and a future.