1. A teacher can show me a new posture and can give adjustments.
2. I can get infos from other yogis of the community (ashtangi.net, ezboard)
3. I can do the new posture more often than the other postures.
4. The positive attitude can help. Patience, the optimism that it is doable.
5. Visualization can help. I can imagine that I'm already in that posture.
6. I can read books and watch videos in order to copy what I see.
7. And again: practice, practice.
8. I can make a new posture to a favourite posture.
9. To blog helps to stay motivated.
10. I can hold the posture longer as usual (10 breathes?) so that the body can relax and can get used to it.
What else can be helpful?