What’s the secret of making great speeches and presentations?

Confidence and how well you know what your presenting. Everything else should be a breeze when you know what you're talking about.

Information about the topic Be normal, And it depends upon the topic that how much serious or funny you should be during your speach.Information about the audience who will hear it.Understanding that what are your goals or what you want to achieve after your speech is finished, Self confidence, motivation, and a feeling that the people sitting in front of you are just like you, they are not better and they are not lower than you, they are your equal, cause a message on an equal personal level riches and creates the positive and progressive effect. and always keep your Air conditioner turned on. :-)

1) Confidence, be prepared and know the topic in great detail.2) Sense of humour, to be animated and fluid.3) encourage / egg, audience partipication and contribution. Or give examples that relate to actual events that occur to some of the audience, so they feel and can relate to you personally.

Preparation Is The Key , Confident In Your Speech And Focus On Your Target Audience  .