Usually the emphasis on making an effective speech is what you do in preparation before the presentation begins. But if you speak very much, what you do after the speech can help you become a more effective speaker.
As soon as possible after the speech, write down impressions of how you felt the speech went. Answer at least two questions about the speech: What was the best part of the speech? What part of the speech can be improved the next time?
Some of your best ideas will come to you as you are speaking. Write them down as soon as the speech is over so you can be prepared to use those lines or ideas the next time you speak.
Think about the peaks and valleys in the speech. Consider when the audience seemed to listen best and when the audience seemed restless and disinterested. Write down your reactions while they are fresh on your mind.
Talk to someone about the speech within the first day after your presentation. You'll remember best what you talked about and you might discover a better way of telling a story or making a point as you summarize your speech to a friend or colleague.
Keep track of stories you tell and case studies you include so you'll not repeat yourself if ou speak to that audience again. In addition, keep records of how long you spoke, what you wore, key people you met, and anything unusual about the speaking context. Occasionally look back over your records of individual speeches and look for trends in your speaking that you are unaware of. When you speak to this group again, this information will be the basis for your audience analysis. This is especially important if you speak frequently within your company and your audience will be made up of listeners who have heard you before. You don't want to develop a reputation for telling the same stories over and over.
If the group has speaker evaluations, ask that a copy of the summary be sent to you. Look for any pattern in the comments as you analyze the summary. If one person said you talked too slowly, it may be a personal preference and you don't need to give much consideration to the critique. If four or five people make that comment, however, then you might want to consider changing the pace of your speaking for the next speech.
Certainly your main concern should be with your preparation before the speech. However, don't underestimate the effort of what you do in analyzing the speech after the audience has left the room.