PowerPoint guidelines help you measure distances between objects so you can position them in an orderly fashion on your slides, but there are only two by default. Learn how to get more.
PowerPoint's guides intersect the middle of a slide, resembling a gun sight, just a bit, if you ask me. You can use these guides to measure the distance between objects and to position things accurately.
Guides are easy enough to display. Just right-click the slide, choose Grid And Guidelines from the resulting context menu, check the Display Drawing Guide On Screen, and then click OK. By default, there are only two guides, but you can move them. Simply click a guide and drag it.
Moving guides around can present a bit of a problem if you're working with a lot of objects. Sometimes, it isn't the guides' position — you simply need more of them. The good news is that you can add as many guides as you need. This is one of those tips that seems simple and intuitive, especially if you use Office products a lot. Yet, I just discovered it. I can't remember that I ever needed it before, which probably explains the lapse.
To add new guides, press Ctrl and drag a guide. Instead of dragging the existing guide to a new position, PowerPoint generates a new guide.
This works in all versions, including the newest, PowerPoint 2007.