In the context of leading worship in song, I have suggested that leaders avoid extended periods of leading with closed eyes. Here, in the context of speaking informationally, it is a similar matter: it is important to communicate with those being led.
When making announcements, look primarily at the people you are attempting to communicate to, not at any printed information you may have with you. Of course, there will be times that you need to refer to factual data, but it helps to connect with people if you will look at them when you are telling them something. Look at your audience first, then refer to paper if you need to do so, then look at your audience again. What you are doing, in effect, is linking information with people. If you do not communicate with your eyes, you appear to be less convicted, less interested, less invested … and the information is much less likely to be delivered meaningfully and enduringly into the ears of the people.