You should have a strong command over the subject you are going to talk about. Make sure you have compiled major points that you want others to know.
Try to start speak in a conversational manner while using sound bites which will create more impact on your audience and they will become attentive. You can say it in different ways like, few words can change the course of life and I am going to reveal those few tactics.
Make sure that you have details to prove your sound bites as only saying big words will bring you no response from the audience.
Always use action words that can inspire people to do something and avoid using passive sentences. You should also include analogies and metaphors which you speak.
Try to use emotional words in your speech that could stir the feelings of your listeners which will bring their attention towards you.
Try to use minimum words but make sure that these words grab positive and effective impression on all of your listeners.