Be persistent!!! You have to train her. Use rewards. Ignore the fits. Put her on the floor if she has one. Have her sit at the table to play, not just to eat so she can get used to it and is actively engaged with something fun. Let her "set" the table with at least spoons and napkins so she has some ownership. Have her put a doll or stuffed animal in her seat and buckle her in for practice. Praise the doll. Pretend to eat with the doll and keep praising! You may want to keep using a high chair at restaurants. The wood ones are made for big kids!!! The plastic boosters they provide slide off most chairs easily or have to sit so far back in a booth that she can't reach the table. We went straight from the high chair to sitting in a regular seat with my older ones and will probably do the same with my baby as he grows. For dinners out, bring a special bag or backpack with special things inside. Things that can only be played with at restaurants. Small play-doh containers with play-doh scissors (they have no sharpness), color wonder paper and markers, invisible ink pads, special writing tablets with unique colors, sticker sheets and papers, washable self inking stampers, etc. With Halloween and Christmas coming, there will be tons of trinket type toys that are perfect. Those little tic tac toe boards with the pegs are a good example. She can't follow the rules yet, but with supervision, she'll love putting the pegs in the holes. My big rule was that once we sit, you don't get up. If you let her up, she probably won't sit back down. Distract her with the goodies in the bag or some crackers to keep her seated when she gets antsy. You may also want to take her out more now to get her used to sitting before the big Christmas dinners. Practice!! Good luck. You can do it!