Save the Best for Last
Here's a great technique to use in your presentation ― put the best (or most important) part at the end. (It works because people tend to remember the last thing you say more than any other part.)
The most obvious example of this is the simple joke (which as I've warned in other places, you might want to avoid). It's important to tell the joke well, of course, but it's the punch line at the end that everyone appreciates and remembers.
This applies throughout your presentation. As I've said before, you should close your presentation with a strong conclusion. That's another example of putting the best, last. A strong closing can possibly salvage a weak speech, while a poor closing can ruin an otherwise great presentation.
But "putting the best, last" also applies to paragraphs (or thoughts). Frequently, the last sentence in a paragraph (of your written speech) will be a summary of the idea that you've just discussed, or possibly a segue into the next thought. Either way, it's quite possibly the most important sentence in the paragraph.
This technique can also be used on a single sentence. Consider the difference between "I opened the door and my mother was standing there" and "I opened the door and there stood... my mother!" "Mother" is the important (or surprise) word in that sentence, and so it's most effective when it's at the end.
So whenever you want to provide emphasis, get people's attention, or otherwise make whatever you're saying memorable, put the most important part last!