@ Ask yourself WHY DO YOU WANT TO SPEAK?
Once you know why you want to speak, your confidence gets a boost. Is it important for your business? Is it important for your job? Are you pursuing a noble cause that you want to promote through your speech? Do you want to join politics in the near future? Do you just want to put a point across? Think hard why you want to speak and write it down on a piece of paper and then read it again and again. Is it worth taking the risk (the word "risk" is misplaced here, but I'm trying to drive in a point)? If you find yourself saying "yes," then half the battle is won.
@ MAKE YOUR INTENTIONS CLEAR.
You, on your own, become assertive once you know why you want to speak. Put emphasis on your words, but don't over-do it. I remember attending a workshop where an e-learning expert was giving a presentation. She was so assertive that in a few minutes she became a nuisance and everybody was feeling awkward and funny.
@ MAKE EYE CONTACT
Look in the eyes of your audience. Try to make as much eye contact as possible. It will put you at ease. It also shows whatever you are saying you are saying it with a conviction. If you are afraid of having eye-contact, the best thing you can do :"see the forehead, between the eyebrows of the people".
@ USE QUESTIONS Asking questions makes your speaking session interactive. Get their input. You begin to converse with your audience and this makes you comfortable. You strike a friendly note and your audience no longer seems intimidating. Most precarious issues in the international politics have been resolved through two-way communication.
@ POSTURE WELL Use your posture and body language to your advantage. A few points above I had mentioned that you should keep your limbs relaxed while talking. A relaxed posture is a good posture.
@ LISTEN If you listen well, then you speak well. All good speakers are good listeners too. If you listen, you know what other people are thinking of. By listening, you gauge the atmosphere in the room and adjust yourself accordingly. Speaking is not an art, it is not a skill. It is just an expression. The moment you are true to yourself and the people around you, you can speak well.