Fighting

My sister Rachel and I fight more than anybody I know, and most of the time it's over stupid stuff. But how do I get her to quit acting like she's the boss of me? I don't resort to violence, meaning I don't punch, slap or hit my sister. I try to use big words to confuse her. Yet, everyday, usually about the time I wake up, there she is, yelling, fussing, or complaining that I'm not doing anything. I do things, it's just things that she can't see because she's always too fussy. Like today for instance, I kind of slept in until 9:30 10 o'clock this morning. VERY RARE lately. She had a fit. She also inflicted upon herself to clean the whole downstairs and upstairs (not including our bedrooms) so that she could go hang out with friends tonight. However, when she asked me to make tea- which 9 times out of 10, I usually do, I refused- thinking, "why do I have to listen to her?" Even though it doesn't matter if I were to fight her or not (which I did) I still ended up making tea because the referree(mom) put a stop to things. So before matters got worse, I went and made tea, kinda cleaned up the dining room and kitchen and then told mom that I did all of that and would be in my room if SHE needed me. Even then, I wasn't done with the bickering. I am Jake and Emily's English teacher/tutor. Any problem in English they come to me. And I had a double dose of it today. They are both very different when it comes to their school. Emily, all I have to do is show it to her about 500 times, and then she'll get it. Jake is a constant battle. He will get an attitude, fuss and bang his head on the table before he even asks for help. And it's the same questions over and over again. He gets the hang of it, but then he doesn't check his work, and then when I check it and find all of those very little mistakes that change the whole sentence pattern(i personally hate those) it pisses him off and I'm in for a bumpy ride.