There is a saying that "to get respect, you have to give respect." Try to "bite your tongue" the next time Mom gives you an instruction or criticizes you, instead of arguing and/or resisting her. Even though she may not acknowledge it, your mom will appreciate your change in behavior. If you feel that she has been unfair, or you feel really mad that you didn't speak up, quietly go into another room, takes deep breaths of air, and punch a pillow to release your frustration. You may feel that you didn't get to say your peace, but at least she did not call you names and/or ground you.
You cannot control how your mother behaves towards her other daughter and how she "flaunts her power." Concentrate on the things that you do have control over. When you remember the way that you and your mother used to be best friends, how did the two of you act towards each other to make it that way? If it's hard to have conversations with your mom the way that you used to, try just simple stuff first: tell her you love her each night before you go to bed; leave little notes for her on the kitchen table, her pillow, and/or on the fridge; ASK her for help and permission and other things, instead of TELLING. If you think of some more things that bring you and your mom closer together, let us know about them. We can pass along those ideas to other kids who contact us.
We're so glad that you have found YourLifeYourVoice too! We look forward to hearing from you again!
Take care,
Jacque