The Scheduled Awakenings technique has been successful in decreasing night wakings, the occurrence of night terrors, and shifting the wake up time later (mainly case-study based evidence for decreasing night terrors and early mornings). The technique has only been empirically tested with children between 6 months and 2.5 years, but should theoretically apply at any age. It does not assist with self-settling, or bedtime struggles.
For a review, see this post and podcast:  https://www.practicalresearchparenting.com/2015/03/19/research-based-sleep-training-methods/

To address night terrors:

1. Determine when your child usually has night terrors (this is likely to be somewhere between 1-3 hours after sleep onset when particularly tired).
2. Slightly arouse and comfort your child 15-60 minutes prior to the predicted night-terror time.
3. For occasional night-terrors, do this on nights when you predict night terrors (commonly on days when over-tired).
4. For frequent night-terrors, do this every night, then gradually fade out scheduled awakenings.

To address night wakings:

1. Determine when your child naturally wakes at night.
2. Slightly arouse and comfort your child 15-60 minutes prior to the natural awakening time.
3. Gradually fade out scheduled awakenings.

To address early mornings:

1. Determine when your child naturally wakes in the morning.
2. Slightly arouse and comfort your child 15-60 minutes prior to the natural awakening time.
3. Do this for at least 3 days, then try removing the scheduled awakening.

This approach works by disrupting the sleep cycle, such that your child enters the new sleep cycle and sleeps through the usual wake up time. With repetition, this can get them out of the habit of waking at that time. If you don’t rouse your child enough, or rouse them so much that they wake fully, it is unlikely to be effective. Ideally, you want them to stir without opening their eyes.

This approach has had very variable results. For some children it can work quickly, for some it can take 5 weeks to work, for others it doesn’t work at all. Unfortunately we don’t know what factors determine whether this approach will be successful. Some have suggested that it is particularly effective for night terrors. For more details, see the podcast linked to above.

A modified version of scheduled awakenings involves slightly waking your child just before you go to bed.

Please add your experiences with this approach in the comments below. Please provide the age of your child when you tried it, and how long you tried it for. If it helped, please share the effects you saw. If it didn’t help, why do you think it didn’t work in your case?