One of the nastiest blunder you can make as a motivational speaker is talking for a long duration. Your speech will not only drive people to never, never land but it might also make many people go mad downright. It is never taken into consideration even if your whole lengthy speech was motivational or brilliant. The audience will leave the hall saying "the speaker loves to speak a lot but we are not the lengthy listeners" Don't allow this to happen in your case. Just say what you have planned to say and sit down. Before you decide to sit down, just let the audiences know that you are going to end the talk.