Honestly you want the best way to do it? Next time she goes in your room, which you should have locked all the time anyway, and does something bitchy, give her a good whack or push her into something. I'm not even kidding, you need to make her realise you're not her bitch, and you need to stand up to her. Yell at her, come up with something smart and make sure she knows you're not happy about how she treats you.
You REALLY need to speak directly to your parents, starting with something like "mum, im losing my mind because of my sister, its not fair how she treats me etc" tell them shes been a complete bitch to you your whole life and won't mind her own fucking business (give examples, ie. "last week she walked into my room and fucked around with my computer, that isn't fair and she needs to mind her own shit"). If they just shrug it off then you need to make recordings, or do anything to prove to them she's acting that way. But really you need to speak up and defend yourself, don't just sit back and say "oh well, she got me in trouble better just accept it and move on". That's not good enough if you ever want to change the situation.
If that doesn't help, do something more harsh like going to a counsellor who will contact your parents. Or go fuck with her stuff. Luckily I don't have family like this, but if I was in this situation, I'd be fucking mad and would take action the first time it happened.