A teleprompter lets you keep eye contact while you read. Done badly it looks like you are reading. Done well it looks like conversation.
Write for speaking
Use short sentences. Read your script aloud and change anything that makes you stumble. Write numbers and names the way you say them.
Set the text large
You should be able to read it from where you actually stand. Large text with only a few words per line keeps your eyes from sweeping across the screen.
Keep the text near the lens
The closer the words are to the camera, the less your eyes seem to move. On a phone, put the text at the top of the screen near the lens.
Slow the speed down
Start slower than you think. You can always speed up. Practise a paragraph before recording.
Add pauses and breaths
Mark places in the script where you take a breath. Pauses make a speaker sound confident.
Record a short test
Record ten seconds, watch it, and adjust speed and size once before you do the full take.
Our app has a Teleprompter, and a version that follows your voice, both in testing. Neither is released yet.