Although your speech notes may just be keywords, you will have somewhere the full text that has been through many amendments and rewrites. But no matter how good the speech, it is how you say it that will stay with your audience. It is a speech you are delivering – you are not just reading from your text.
Published somewhere are percentages as to how much people notice about a speaker. I recall that what the speaker actually said is way down the list, but don’t be fooled by this. Everyone present would have remembered exactly what you said if it had been unrehearsed and poorly written nonsense.
What people notice most, of course, is you and although you can’t help how you look, just make sure you look right for the occasion. This is not about being dressed right for the occasion – I’m sure you will get that right – this is about presenting yourself. In practice, this means being “bigger than you are.”; projecting yourself by being aware of your body language, gestures and the tone and pitch of your voice. If your speech won’t be remembered in detail, you will want to make sure that you are.