I only have to work at it every minute of every day.
Thirty+ years ago I was thrown off a horse at the canter depart. It resulted in three crushed vertebrae. "You'll have arthritis when you get older," the orthopedic surgeon warned.
He was right. In my fifties the back pain started bad and got worse. Then I took up ice dance.
It wasn't that the skating itself made the back pain go away, in fact I used to ache from head to toe after an ice dance lesson. My on-ice posture wasn't getting any better, no mater how hard I tried. And trying to hold dance posture resulting in eye-watering pain.
One day at work while I was hunched over my keyboard a pain shot through my back. In response, rather than go to the doctor and get some painkillers, or contemplate surgery, I decided to sit up straight. I forced myself to do all those things that the posture nazis recommend. I adjusted my chair, fixed my keyboard, and got up to walk around (even if only to the printer) every hour. I stopped IM'ing or emailing people. I got up and walked to their desks. I threw my shoulders back, sat and stood up straight, and kept myself moving. I also started doing 40 minutes of stretching and flexibility exercises every day during lunch.
When I started taking lessons from Coach Cruella, she was able to give me techniques to translate good off-ice posture into on-ice posture.
IT TOOK TIME. But it worked. I now have no pain in my back when I skate. If I hold an awkward position for a long time I'll feel a crick, but not pain. My dance posture is pretty good for an elderly recreational skater. In Killian I have my shoulders touching my partner's supporting arm. In waltz, not only is my back straight, but my butt is tucked down so it doesn't stick out (and I've seem some recreational skaters that are better than I am, that don't do that).
A few weeks ago I saw Dance Coach coaching one of the freestyle girls in Fiesta Tango. She had that lean forward freestylers tend to have. I realized I had better posture in hold than she did, even though she was a much, much better skater.
Then in my last lesson Dance Coach put me in Killian and faced us toward the glass to look at our reflection. "Looking good," he said.
All it takes for me to get good ice dance posture: I work at it every minute of every day.