Evernote (EN) fills a gap in my presentation preparation. This is more nuts and bolts and less philosophy, though there's a bit of that here.
I'm often asked to present and explain complex technologies and concepts to a broad audience. Sometimes the request comes with little time for preparation.
Occasionally the lack of notice is okay. I keep general slide decks (e.g. Microsoft Office PowerPoint Presentations) ready to go. I know the material well and engage the audience, to the point that a deck on display behind me is informational. The problem manifests when I forget portions of my presentations, just like when you know a song but forget the middle verse. The same happens when the discussion heads down an interesting tangent.
In such cases I use EN to record the presentation for continual improvement, but that doesn't help ensure I get the content across I intend to.
When I hit an interesting tangent I can forget why I'm there in the first place.
The problem expands when I need to convey something new and soon. I stumbled on a solution accidentally using EN. EN has a record audio button in the note dialog. I use it to capture tasks and notes when I can't get to a PC. I use it to record my talks as mentioned before to help me improve my presentations.
While I'm used to recording my talks, recording the pre-presentations is the "ah-ha" moment. In the EN note I put the key concepts and points in the talk. Then I use the record option to capture my initial brain dump ramblings on the topic. I play it back, capturing the concepts and details I like and discard the less salient points.
Eventually I draft the deck in the same note. I'm a huge fan of Garr Reynolds Presentation Zen and the presentations of Steve Jobs, Guy Kawasaki, Ze Frank, Alton Brown's Good Eats (one of the best show-&-explain examples out there), and those who let the display set the story but the presenter to tell the story. This is the antithesis of the "death by PowerPoint" or "bullet pointed to death" exaggerations of boring to bad presentations.
For each slide I use EN to grab the pictures that might help convey the message I want to communicate. I write the slide text and any supporting materials.
As I iterate the mirror & timer test of my deck, I record them. I can go back and listen to older versions to make sure I move forward without losing content. I adjust the note to reflect the changes.
The last step I do is actually put the slide deck (ppt) together.
The folks who run such sessions want the presentation deck way ahead of the actual presentation. When they do, I give a dummy deck then send the final version as adjacent to the session as practical. Worst case I'll ask to use the version on my USB stick. Those who want to vet content don't care for that technique, but a live audience can surface other concerns.