Consider the standard, garden-variety, dull-as-ditchwater business presentation.  A business person wanders to the front of the room, nervous as an auditor in a gambling den.  People look up briefly from their Blackberries, and, seeing nothing of extraordinary interest yet, return to their email and to-do lists.  After fumbling apologetically for a while with the technology, head down, fingers flying, the presenter finally achieves Power Point, and starts by saying, “Here's my agenda slide.  What I’m going to talk to you today about is…..” 

The speaker still hasn’t gotten the attention of the audience.  Why should the audience pay attention?  Several minutes have gone by and all that’s happened is prologue.  The audience is still waiting to hear something new. 

The speaker has wasted a lot of energy on the technology,  and begun to spend the goodwill that audiences have for all speakers at the start, because they want their time to be used well. 

This is not effective communication.  Everyone’s time is being misspent.  Why do it?

Instead, imagine the speaker striding briskly to the front of the room, launching into a story about the perils facing the industry, a story which has the audience nodding in agreement and eager to hear more.  The speaker then asks a couple of key questions of her listeners to involve them and ensure that the presentation remains relevant and focused on the audience’s needs.

The difference between these two scenarios is focus.  The speaker should always be focused on the audience, while creating the speech, rehearsing it, and delivering it.  Then, if the speaker has done her job well, the audience will be able to focus where it should:  on the content.  Right from the start. 

Rehearsal is of course key in this regard, because no speaker can focus effectively on the audience if she is worried about the managing the content in real time.  It's in rehearsal that a speaker will find the ease necessary to take her focus off of herself, or the content, and free it up for the audience. 

So your duty as a speaker in preparing a speech is to get the content and delivery down so well that you can focus on what you should during the performance itself:  the audience.   Which will allow the audience to get the content. 

That’s effective communication.