Hi, I'm firmly of the view that good public speakers develop through preparation, hard work and experience.  I think you'll find this article most helpful:

https://www.theguardian.com/higher-education-network/2013/may/10/public-speaking-academics-10-tips

I wish you all the best.

Sincerely, Matthew

By preparing and doing it.

First of all, I agree with our colleague Asma Mehan.

I think almost of our colleagues, are overcome the shying barriers, because they already and many time stand in front of people and students, so it is so easy for any lecturer to be a confident public speaker.

How to be confident speaking to a large audience: I will say a big part of it is having a good grasp of your subject, being comfortable in yourself, being relaxed; and the rest will be practice and growing in experience with time. Each good outing will provide positive reinforcement. If you get honest feedback each time to enable you correct mistakes and build on your strengths then you can only continue to grow in the art.

First, "practice makes perfect." As many colleagues have pointed out.

Another critical ingredient has to be mastery of the subject matter. It is obvious, in any presentation, when the presenter has only a shallow understanding of the topic. A confident speaker is one who can drill down into the details, or into counterexamples, or into controversies related to his presentation's topic, even when such extra material is not being presented right now. A confident speaker is one who cannot easily be blindsided by questions from the audience.

And too, I don't think one can deny that personality is a factor.

As a student, or anyone speaking on emerging research topics for that matter, the speaker is being made to push the limits of his or her knowledge. Mastering a subject will normally take years. In these cases, acknowledgement of the limitations, as opposed to trying to hide them, can also give the speaker confidence.

In short, perhaps one can say that confidence in public speaking comes when the speaker does not feel the need to become defensive.

I agree with the insightful views of the colleagues. In addition, it helps to bear in mind that no one knows your topic better than you.

Regards

http://www.amazon.in/Art-Public-Speaking-Dale-Carnegie/dp/8184302614/ref=sr_1_1?ie=UTF8&qid=1488513227&sr=8-1&keywords=public+speaking

"Most people report that giving a speech is their greatest fear. And yet the ability to give a speech is one of the most valued business skills today.

Try these 10 tips to get over your nervousness and to develop confidence while speaking.

1. Expect to be nervous.

Even experienced speakers get nervous. Don’t try to eliminate your jitters. Turn them into energy you can use to boost your delivery.

2. Prepare.

Know what you are going to say – and why you want to say it.

3. Practice.

Speak to supportive audiences in small forums where less is at stake – at a staff meeting or a PTA meeting. Join Toastmasters or take a Dale Carnegie course. Work with a coach.

4. Breathe.

In the thirty seconds before you begin speaking, take three slow, deep breaths through your nose, filling your belly. As you breathe out, say silently to yourself, “Relax.”

5. Rehearse.

Stand up and walk around as you practice out loud. Don’t memorize your speech or practice it word for word. Talk it through, point by point. Imagine you’re explaining your main ideas to a friend.

6. Focus on your audience.

Stage fright is rooted in self-preoccupation. (“How am I doing?” “Am I making any sense?”) Stop focusing on yourself. Focus, instead, on your audience. (“How are you?” “Are you getting this?” “Can you hear me?”)

7. Simplify.

Most speakers try to do too much in a speech. Then they worry about leaving something out or losing their train of thought. Aim, instead, to communicate one basic idea. Keep it short and simple.

8. Visualize success.

Practice relaxation techniques in the days before your presentation. Lie down or sit comfortably in a quiet place. Breathe slowly. Close your eyes. Imagine your upcoming speaking engagement. Picture yourself speaking with confidence.

9. Connect with your audience.

Make the audience your allies. Talk to individuals before your presentation to get to know them. Look them in the eye as you speak to them, one person at a time. When your audience sides with you, your job as a speaker becomes easier.

10. Act confident.

People won’t see how nervous you are. (They can’t tell if your palms are sweating or your knees are knocking or your heart is pounding.) So don’t tell them. Smile. Stick your chest out. Look confident, even if you don’t feel it."

1. Lack of attention to contacts

2. Talk to study (using key words)

3. Due to eye movements and contacts with moving eyes

4. Not thinking what will happen

5. Moving the hands, to impress

6. Self-confidence

Speaking at events is a great way to enhance your status as an expert and generate PR for your business. However, becoming a great speaker is an art, not a science. The good news is that with some tips and some practice, you can leave a lasting impression that you will want people to remember.

Here are some easy ways that you can become a better speaker.

1. Memorize concepts, not content.

You may think that the best way to give a flawless speech is to memorize the content word-for-word.  But trying that can create a lot of problems for speakers. Memorization not only lends itself to sounding over-rehearsed (aka not natural), but also, if your mind goes blank at any point during the presentation, you will lose your place and potentially create an awkward silence. Or worse, start to panic.

2. Chat up audience members before your presentation.

Meeting with the people you are going to be speaking to before you give your speech has several benefits. First, it warms them up to you. Second, it lets you gauge their sense of humor, which is particularly critical if you are a speaker that tends to let a curse word fly or uses bold and provocative stories or language. Finally, you can glean insights to incorporate into your presentation. 

It’s incredibly effective to use audience members as examples or transitions in a speech because it creates intimacy with the audience and more engagement. If you are talking to small-business owners about marketing and Joanne, for example, told you a great story about how she used an unusual marketing tactic, incorporate Joanne and her story into your presentation. “Speaking of clever marketing, earlier I was talking to Joanne, who is sitting in the third row, and she told me how she used a PR stunt with 400 kittens to get new clients…”

3. Enhance your visuals and audio.

I think most speakers know to not read directly from slides (and if you didn’t before, you do now). If you do use slides during your presentation, use them in an unexpected way. Include a short, fun video or use some photos with humor. 

I saw one presenter who, when he was talking about how people want to do business with trusted brands, had a photo of a beat-up old van with “Want some candy?” spray painted on its side to illustrate why you don’t do business with strangers. Another keynote I went to recently had a DJ who changed the music to underscore themes for the story. Or even consider having an illustrator create some great art for key messages. At least evaluate having your presentation slides created professionally. These tactics can take your entire presentation up a level.

4. Flip your mindset to ease your nerves.

Even the most seasoned speakers can get nervous prior to presenting. The most effective way to take the pressure off of you is to change your mindset and think about your audience rather than yourself or the speech. Remember that you are there to provide them with valuable information and if the audience members leave with one or two new items, reminders or a new perspective, you have made it worth their while. Focusing on being helpful or in service of the audience, instead of on yourself, can help you to relax.

5. Get interactive. 

One of the best speakers around is Michael Port, who takes audience participation to a new level. During his presentations, he has the audience repeat key messages back to him or make gestures back of the takeaway points of his speech. This keeps the audience involved, but even more brilliantly, it gives them devices to remember the material. I often will stop in the middle of the speech to ask audience members to throw out examples of ideas that I present as well. 

As you plan your speech, think about where you can involve the audience and what devices you can use to involve them in the presentation so that you are talking with them, not just to them.

"These changes in habit and thought can hopefully help you:

1. Stop trying to be someone else.

If you are funny, be funny. If you are informal, be informal. There is no one right way to be a great speaker. Rather than a performance, think of it as sharing your ideas and experiences to help others.

I’ve seen so many interesting people put on a mask when they walk in front of a room. If you communicate very differently as a speaker than when talking with your co-workers, you may have on your “speaker disguise.”

Let yourself shine through and the audience will connect with you—flaws and all.

2. Don’t look for approval. Focus on contributing.

This was a big one for me. If you have your mind on I want to be good, then you will stay inwardly focused. Instead, think about helping even one audience member see a familiar topic differently, hear a great idea they can use or receive needed encouragement.

So ask, Did I have an impact? This outlook is counter to I hope they like me, which makes it all about you—not them.

3. Practice. A lot.

I wish there were an easier way, but I haven’t found it. The more I speak, the more comfortable I get. I think it’s a little like playing Major League Baseball—the crowds won’t get to you if you are comfortable at the plate.

Look for simple ways to get that practice. I know people who have joined groups, like Toastmasters, to get more practice. Or one of my clients volunteered to facilitate the leadership meeting to increase her confidence as a speaker and facilitator. You can also volunteer to speak on your area of expertise at local conferences or association meetings. These smaller venues outside of work can be a safe way to learn and practice.

Nothing replaces getting out there and in front of the room.

4. Watch TED Talks.

There are thousands of TED videos that serve as an instructional library on speaking. These presenters have spent weeks preparing so they can give it their best. Watch how they share their thoughts and connect with the audience. What worked for them that feels right for you? How did they grab their audience’s attention early?

The other thing I love about TED is the visual reminder that there is no one right answer on giving a great presentation. All kinds of personalities and styles can keep you engaged—not just the entertaining extrovert.

5. Video yourself speaking.

Before you think, I don’t have the resources or the budget. This is simple. Just bring an iPad and set it up the next time you speak to a group. Ask a colleague to help. It can be very low key. Nothing replaces a video of you in action because how we think we show up isn’t always the way others see it.

I am conversational and so I like to move around as I talk. I learned from video that sometimes I roam too much. So I had to limit my “travels” a little. I’ve had colleagues and clients learn that they were looking at their slides more than the audience, making statements that sounded like questions based on their inflection or talking too fast. This client learned to slow down and use pauses for great effect. She increased her impact just by watching a video of herself.

Only video will reveal what others see and we don’t.

6. Know your content cold.

This doesn’t mean memorize what you want to say—but go through your key points multiple times so that it’s very familiar and firm in your mind. Prepare well. When you get nervous, really knowing what you want to say will help calm the nerves.

Even when I’m speaking on very familiar topics, I always do a couple of run-throughs. I improvise and adjust, but my core remarks are top of mind before I start.

You can do this. Get your mind focused on impact rather than your personal report card. And, practice. Every time will get a little easier"

http://www.success.com/blog/6-tips-to-be-a-more-confident-speaker