I am not a big fan of animation, spectacular effects do not support a serious business message and documents with animations do not convert well to PDF for emailing.
Sometimes there is no escaping though, especially when you need to explain components of a complex system. The best way to do this is to add elements one-by-one through a series of clicks.
The usual way to do this is to use pop-up animations. However, these can be cumbersome to edit: you often forget one item in a group, and have to start all over again.
There is an alternative: cover the critical elements in your slide with boxes and remove the boxes one by one. Easier to edit. You can even make it more sophisticated by given the boxes a 10% transparency: the viewer sees sort of what is coming, but not completely. When you want to PDF and email a version of your document, you simply delete all the boxes which leaves the full diagram intact.