Two must-do's for singing deal with expanding the vocal apparatus (voicebox, chest, diaphragm) in the outwards and downwards directions:
- Puff out ribs when inhaling air as well as during singing
- Lower the diaphragm downwards when inhaling, or firm it up when needing support for hard notes
How about expanding the vocal apparatus (upwards somehow) so that your voice doesn't sound like it's stuck below "a glass ceiling"? I saw it described this way in a video, so I do not know how to express what I mean in a proper way, but I hope somehow knows what I mean, or can rephrase it with a better-known description of it. That feeling that there is something "at the top" of your vocal apparatus that is holding down or suppressing your sound: What body technique is there to blow past that glass ceiling in order to have an unsuppressed voice during singing?
(this question is not about pitch, vocal range, or hitting high notes. Re: an edit I had to rollback: While it is about vocal power, it is not limited to strengthening just the existing upper vocal range since that merely would fall into the category of vocal range as well)