First of all you need to think about what you are going to say. Write a list of things you want to talk about and include them into your speech. Make sure that you bring a small notebook, in which you can have a list of the points you want to mention. That way you won’t forget about them. Whatever you do, don’t stop speaking when you forget something. Just pretend that everything is fine and make something up. It may seem hard at first, but if you get the hand of it, it’s going to get easier.
I hope this helps…