Public speaking is not a matter of life or death.You should learn to relax when you are speaking in front of a crowd. When you miss out on something that you have on your notes, you should remember that no one except you would know that. Aside from that, no one is going to shout at you if you missed an image in your visual aids. Know your audience.Learning more about your audience can help you a lot when it comes to the kind of speech or presentation you want to have. For example, if you are going to present in front of professionals, then you should keep it formal, but dont forget to throw out some jokes. This can keep them from becoming bored.