Before you write a single word, get quiet and ask why. Why are you speaking? Why does the audience need to know this information? Why are you the right person to convey it? Why is this the perfect time for them to hear it?
Starting from why keeps you focused on what you need to convey rather than getting distracted by extraneous information. If the audience doesn’t need to know it, get rid of it. Be a ruthless editor.
Once your speech is whittled down to the essentials, you can give it room to breathe. But you can’t start there. You start by putting each and every idea through the “why” test. If it doesn’t fit your why, it has to go.