Record yourself making public speech and listen. There some very easy to correct mistakes, habits and mannerisms that remove power from speech. For example:

- Run-on sentences or not pausing enough between important sentences. If you have tendency to hurry up, it's less convincing and memorable. If you stop after a sentence, it sounds like you said something important and emphasizes it.

- vocal fry and nasal voice for women. For women in certain age groups there is culturally adapted creaky voice or alternatively nasal voice. It's possible to get rid of it with very small amount of practice. It's almost never normal voice, just adopted mannerism.

-"Uptalk" is the habit of ending all sentences with rising sound. Everything sounds like a question.

- I don't know the name for this, but some male speakers have tendency to start sentences in discussion with high pitch fast speech that slows down towards end. Even some very high profile journalists and podcast hosts have it to some extent. Ezra Klein for example.