Do you know the difference between practice and rehearsal? Seems not many people do.
Practice is reviewing your script or slides while you are at home, in the office or on the train to work. You think about what you are going to say and what slides you will show. This is not rehearsal!
Rehearsal is where you actually stand up and run through your presentation as if you were presenting it to your audience. You rehearse your vocal variety, your gestures, your visual aids, your pauses, pacing and your interactions with the audience. Rehearsal can make the difference between a good speech and a great speech.
Think about your own presentations, are you practicing them or rehearsing them?