‘AH’s’, ‘um ‘s’, ‘er’s’, and similar speech stumbles need to be avoided for the sake of fluency. Too many glitches may have the audience thinking you are unclear on your subject. Aim for ‘zero’.
Use notes as prompts, but try and avoid detailed reading. A speaker is more effective when speaking rather than being slavishly locked into notes. Notes can reduce the speaker’s confidence.
Consider vocalisation, the pitch, rhythm, intonation and vibrancy of voice. Live your message through your voice. Articulate carefully and correctly, and never come with a gabbling rush of words.