Prepare physically and emotionally as well as intellectually. Start at your best...(like an athlete)...rehearse the opening sequence.
Prepare for speech not print ... use the immediacy of language not "literature".
Research ... ask the right questions. Who is the audience, what do they want to know, what do you want them to remember? etc
Bullet points ... know what you want to say, not the words you are going to use. The delivery should have a sense of spontaneity.
Have three main points ... create a narrative line.
Talk to not at your audience ... talk as if to one person and move them around th audience.
Energy, vocal variety and vocal and facial expression are essential for audience engagement and involvement.
Imagine the room is 50% bigger than it actually is ... fill the space with your energy and presence.
Timing ... less is more! Edit rather than add!
Style and substance ... aim for a balance between the content and your personality. People remember information because of the person who told them!