If you want to be successful you should strive to make each aspect of your presentation a little better than your previous engagement.
One way to do this is to have somebody in the audience who will give you an honest appraisal your performance. Try to select somebody for this role who is a good voice coach and who is skilled in the organization and presenting of material in an effective manner.
And then you be willing to their appraisal of your weak points especially. We all have them no matter how many presentations we have given -- just like professional football or soccer plays.
The most successful contestants on American's Got Talent spend hours practicing the techniques learned from special coaches assigned to them.
As professional speakers and presenters we should do the same thing.