1. Abruptness, that is, just stopping, perhaps from fear or from the thought one has gone overtime.
2. Multiple conclusions. A speaker should avoid saying "in closing" or "in conclusion;" he or she should never do it more than once.
3. Not summarizing. The conclusion must look back to what has been said.
4. Indefiniteness. I call this the Forrest Gump conclusion, and everyone knows immediately what I mean. "That's all I have to say about that." It's funny; of course no one does that, right? Actually, they do, in so many words. "Well, I'm finished," or "That's about it," or "That just about wraps it up" are some variations.
5. Rambling, or simply not being able to finish, so one just keeps talking. This is the worst because it is what the audience remembers. It would be like spending the day at DisneyWorld and going back to your car only to find you're locked out. It makes something that could have been memorable seem very, very long.
These five "no-no"s can be replaced with some practice and knowledge.
- First, whatever you did in the introduction is relevant to the conclusion. Paul Harvey, the great radio host, had a segment called "The Rest of the Story." The conclusion can tell "the rest of the story." Whether a story, historical incident, personal anecdote, or quotation was used in the beginning, it can be finished, referred to, or re-emphasized in the conclusion.
- There is never a situation where summarizing is inappropriate. (Don't you love hidden double negatives. They just obscure meaning. Translation: always summarize, somehow.)
- Save the best to last. End big. Climax. Leave 'em laughing, leave 'em crying, leave 'em wanting more. End a tad earlier than expected.
- Try not to signal with your body language that you are done, such as closing notes. You can do that after the last word; you should pause before leaving the lectern anyway.
- I am ambivalent about saying "thank you." There are times it's appropriate, but it's overdone. We say "thank you" and "I'm sorry" so much that there meaningless to it.
- Definitely do not apologize, in word or spirit. Nothing should indicate a sense of insecurity or uncertainty with what you have said. An apology only says "I've just wasted x amount of your precious life time" or "I'm a fool and don't know what I'm talking about."
Conclusions take time, 5-10% of the whole speech, and they are often ad-libbed, with the speaker figuring "I'll think of something when I get up there." Don't bet on it. Primarily, do not bring up new arguments, topics, or ways of looking at the topic; that will only confuse the listener. The conclusion is for looking backward and provding unity and completeness, and new ideas will only make the speech look incomplete.