A manual for writers of research papers, theses, and dissertations, 7th edition - Kate L. Turabian 2007

Model your conclusion on your introduction
Presenting research in alternative forums
Part I. Research and writing: from planning to production

Make your conclusion memorable, because listeners will repeat it when asked, What did Jones say? Learn it well enough to present it looking at your audience, without reading from notes. It should have these three parts:

your claim, in more detail than in your introduction

If listeners are more interested in your reasons or data, summarize them as well.

your answer to So what?

You can restate an answer from your introduction, but try to add a new one, even if it's speculative.

suggestions for more research, what's still to be done

Rehearse your conclusion so that you know exactly how long it takes (no more than a minute or two). Then when you have that time remaining, conclude, even if you haven't finished your last (relatively unimportant) points. If you had to skip one or two points, work them into an answer during the question-and-answer period. If your talk runs short, don't ad lib. If another speaker follows you, make her a gift of your unused time.