To much rehearsal, especially as an attempt to memorize everything, may cause more problems than it cures. Use good eye contact. Television anchors establish eye contact. If they read from the text, they usually read from a teleprompter set close to the lens of the camera so that they look as though they are looking at you. Even then, it is possible to detect that they are not looking quite at you, which distracts from their credibility.
Eye contact is essential to establishing credibility.
We dont have to be told that we can't trust people who won't look us in the eye, it's hard wired into our psyche. It wasn't difficult to predict that Bob Dole would lose the 1996 presidential election. Dole could not establish eye contact with the camera. His eyes darted up and down and around and usually away from the camera. Look cameras, individuals and audiences in the eye.