Training in Public speaking is not about having an extensive knowledge of the world. It's not about copying the style and techniques of your favorite speakers . It's not about following a specific set of speaking guidelines/rules. Public speaking is the pouring out of who a person really is... therefore the first and most important thing is to be, think and feel something worthy of being shared.
Unless you believe there is true value in what you wish to share, no tips, tricks or training can ever make you more than just a speaking machine. Self development is fundamental if you truly wish to express your beliefs. You must sit in the throne of your mind and rule over your thoughts, feelings, and physical abilities if you wish to deliver an accurate expression of your unique views.
Training in voice, intonation, gestures, and other methods of delivering public messages will not yield satisfactory results, unless you first have something important to say and the urge of a sovereign will prompting you to say it.
You cannot learn to speak better unless you're first speaking as best as you can. Many learners begin with the HOW... This is not the method I use.
Ancient wisdom teaches us that you learn best by doing, therefore, the first thing any beginner in public speaking should do is speak. Don't waste your time taking notes on the voice and gestures of other speakers.
Once you begin speaking you can improve yourself through the process of self observation and listening carefully to the critical feedback of others.
Experience is the best teacher. Not just your experience but the experience of others as well, which can be used to supplement your learning. By listening to others' stories you can train an empathetic mind and better grasp the lessons garnered from others' experiences.
Being open to greater self knowledge and learning to judge yourself by what you have come to believe "is right" will allow you to become your own best critic. If you're thinking I should do this, I should start practicing speaking then, there's already a little part of you that believes you can do it. It's like what the Philosopher Immanuel Kant said..."If I ought, I can".
I urge you, if you want to get better at speaking, begin speaking NOW! Speak about the things you already know. Speak as precisely as possible focusing on yourself before taking on the outer conditions of the world.
Speak in your own way. Being unique is good!
Speak from the heart. sharing your personal experiences and stories is a key factor that drives great public speaking and allows others to relate to you.
Again, I'd like to say that all the technical methods and tips on delivering an effective speech are secondary.
What is paramount is having a compassionate heart, an engaged mind and a deep understanding of what motivates you.
Until a person understands themselves, learning the methods of public speaking is similar to dressing up a mannequine, The audience might look at the clothes and say "that's nice" but no one will be sticking around for a conversation.