After every presentation, you should always get feedback about how it went. If you have a friend or two in the audience, be sure to quiz them after-ward.
Try to ask specific questions.
Was I loud enough?
Was I clear in my presentation?
Did I beat around the bush?
Did I go too fast?
Were the visuals okay?
Finally, take the opportunity to ask, "What one thing could I improve on the next time I give a talk?"
Thus, each presentation you give offers you a chance to become a better speaker for the next.
To continue the section on Giving Oral Presentations,