Well...it is like riding a bike...Once you have done it a few times, it gets easier.
There is a tip which I have heard many times to get over your nervousness that is to imagine the whole room of people naked. heheh I don;t know it has never worked for me but it might for others heeee....
But seriously, the best way to fight the fear or dread? KNOW YOUR TOPIC inside out, front and back and believe in it enough. We are usually nervous due to our lack of confidence on the topic, we think someone might pop you a question and kill your whole presentation, you second guess yourself..etc. There are technique you can learn to help you with your presentation and showmanship but without the facts...you will not make it thru one smoothly.