Chose Topic of Your Specialisation
If you are asked or invited to speak in the area of your specialisation it is a great help for you, since you have a grip on the subject and can be confident at the time of telling your story to your audience. It can be that you are asked to chose any subject that interests you, and if so go for the subject that you know the best. Do not select a topic about which you know nothing and at the end you have to stand in front of people with your mouth shut, not knowing what to say, and even how to start. The situation will kill you inside, and make the process difficult.
Visit Speech Venue Beforehand
If you know the venue where the public gathering will take place, visit it a day earlier than its happening. You can assess the entire situation and place where you will be standing to deliver the speech.
Know Your Audience
Knowing the people you are going to address can help you gain confidence. For example, if a majority of them are professionals, students or farmers, you will be able to determine how to start and what to say etc, and what sort of questions you can expect to be thrown at you.
Practice and Practice
Practising your speech in front of a group or in front of a wall can help you hone your speech delivering skills. It can further boost your confidence. While practising speak as if you are speaking in real in front of your audience and set the tone of your delivery accordingly.
Use of Hands Gestures
Use of polite hands gestures can help you gain in confidence, but be careful about the choice of gestures, and avoid using any rude ones. Also keep in mind professional and educational level of your audience, as speaking in front of a highly educated class and use of gesture can make you feel awkward.
Try to Be Interactive
If you lose your course with words, let someone in the audience ask you a question. Even you can ask them if they have any question at that stage and if someone raises their hand let them speak out and listen patiently. You can again ask if anyone else has a question and then move on.
Ask Audience Questions
If you find yourself short of words all of sudden, throw a question at your audience, and by the time anyone from them answers it, find your way back to the speech, where you missed it last time.
Ask for Feedback
You can also ask your audience to give their feedback at end of the program. This will provide you some time to get back on the track.