I am not being partisan here but a lot of observers across the political spectrum have commented the Barack Obama was very good at using the teleprompter.
I want to share with you the secrets that Obama had as it is not that hard. The secret is that sometimes you have to speak a little slower, sometimes faster, sometimes louder, sometimes slower, and sometimes pause. You also need to move your head and your body.
That may not sound very hard but when you look at someone like George W. Bush, his head does not move and his tone and volume was pretty much the same throughout which made him sound like a robot. The key is to practice a lot. Forgetting what you say is not a problem. Saying things in a way that make you sound interesting is the real target.
Ronald Reagan was a good teleprompter reader because he brought the discipline of acting into his speeches, not because he was an actor. He used to spend entire days doing videotaped rehearsals with the teleprompter so he could get comfortable with the words- know where to pause, here to speak louder where to soften the tone etc.
You can do the same as well. So you need to practice with a teleprompter and the key is variation. You have to vary the lengths of the pauses, vary your speed, vary your volume, and vary your face and body movement.