Just do the little things that make life miserable for her that she can't really complain about. Eat that last piece of cake that you know she'll want later, but don't let her know. Randomly 'forget' to tell her about some missed phone calls (the more important, the better). This works really well if you're normally really good at passing along messages. After all, no one is perfect, right? When no one will be the wiser, go into her room and misplace one or two things. Then, when she goes looking for them, it takes her a couple of minutes to find them. This is a way to waste their time and they think nothing of it. If you know she'll be using the phone/tv/etc, go start using it before her so that she has to wait her turn. This only works if you can believably act like "How was I supposed to know?" If it's made known in front of you and others see that (ie, your parents), then it won't work. Overhearing her say it, but no one knowing you heard it, is what you want to make use of. Even if you have to end up letting her have her way, it adds a minor annoyance to her. When she's in a really deep sleep, dip her hand into some warm water. The results will be embarrassing for her. If she's on the phone with a guy she likes a lot and you know who it is (by name at least), then be like "Talking to your boyfriend (insert name of another guy she knows) again?" You have to play it by ear at this point, but some key items:Listen for her to be like, "My boyfriends name is (some other guy)". Then you can say the same thing when she's talking to her boyfriend. If she says that the guy on the phone is her boyfriend, be like, "Oh I thought you were talking to your other boyfriend." If she says she doesn't have a boyfriend, be like, "That's not what you said to him an hour ago." It's best to walk away after chirping in the 2nd part, so that she'll either have to argue with you (leaving the guy hanging on the phone and might hang up on her), or let you get away with it. [*]When she has a really important function to attend early in the morning, wait until she's dead asleep and then turn her alarm off OR set it to be 12 hours later. Instead of 6AM, set it to 6PM. Don't do more than once a month. [*]Something else you can do when she has something important to attend is to sabotage it somehow. Big dance? Find a way to make the crotch area look slightly darker than the rest of the dress (best if close up looks normal). Others will talk about how she wet herself. Playing in a band? Dip the mouth piece in vinegar for a few hours (or if it's a hands only instrument, a few teeny dots of honey where her hands will be). [*]If someone calls for her and she's asking you to tell them that she's not there, be like, "Why would I tell him you're not here when you're right in front of me?" Then a second later be like, "Ooooh I get it, you're avoiding him. Ok." and then get on the phone and be like, "She's not here right now." or "She said she's not here right now." I'd recommend not repeating any of them more than once a month at most. Might not change her attitude, but if done right, she should whine and complain a lot to the point that maybe your parents will tell her to stfu and grow up.