The logotherapeutic model is that you decide that this time you will show everyone present how badly you speak for the audience, how much you are sweating so that the sweat is streaming along the carpets that become wet. Then you show how much you are shaking so that all your papers and glasses fall on the floor, Then you show how your teeth are "rattling" in your mouth so that everyone can hear you. Imagine this when you are alone and then when you speak publicly in the real situation. This is called "paradoxical intention". This effort to show how awfully fearful you are is called "hyperintention". Hyperintention inhibits your fearfulness and all of a sudden you can even smile at the whole thing. It really works.
Ehsan - there are many different ways to try to overcome anxiety in public speaking. There are many 'pragmatic' recommendations i.e. practice/dummy runs of the presentation, good preparation, peer review, careful setting up, calming techniques (good sleep the night before, deep-breathing exercises) etc.
However, most anxiety is 'internalised' (perception of how the experience will be) rather than dealing with just the practical aspects of presentation. In this respect, my main advice is to 'think about the audience'. They are there because they want to be there (in most cases). They are far more comfortable sat there. If they were you - they would be feeling exactly the same way. The anxiety/fear behaviour is 'normal' and should be normalised by the presenter as much as possible. Also - even the most experienced of presenters will still feel anxious. It is a way of 'keeping us on our toes' and not being complacent to the audience.
Glossophobia may relate to one’s prior experiences. In exposure therapy, an individual is taught coping skills and, over time, learns to handle the situation that is causing the fear. Cognitive Behavioural Therapy (CBT) is useful because it helps an individual to effectively manage her symptoms. People with glossophobia also may benefit from anxiety management and relaxation techniques, and a combination of several treatments may be recommended.
From another angle, remember, first, that nerves are natural – even for the best public speakers in the country. Use your nerves to propel you through the speech, and know that your physical response to stress will only make the speech all that much more rewarding once you finally step down from that stage. Second, be authentic. Pick a topic that you truly care about, and the audience will be stirred to care as well. And finally, don’t be afraid to aim big. You were chosen to speak for a reason, and you have a meaninfgull story to tell. So take a deep breath and change the world.