For me, OneNote is a peerless app that can quickly change the way students and teachers create and organize digital content. It is intuitive, powerful and works across all your devices. Whether you are an Office 365 school district or not, it is hard to ignore the potential that OneNote has.
To help support teachers in their use of OneNote, Microsoft developed a website exclusively for educators called OneNote for Teachers. It is a great resource that helps you get started with OneNote if you are a first time user, but also includes tips and tricks for experienced users by showing you how to deliver your curriculum with OneNote through tools like the OneNote Class Notebook Creator.
I use OneNote a lot on the iPad, and find it especially useful now that iOS 8 has allowed extensions. This lets me quickly add a website to a OneNote page from Safari, or send an image from my Camera Roll to add to my existing notes. I also use OneNote on my iPhone, on Windows, and will shortly be exploring the Mac version too. OneNote is free for all these devices and all my information syncs quickly and reliably.
Looking for more ideas? I have been developing an Office 365 training site for some of the teachers that I work with. There are resources and ideas on how to use OneNote on that website and you can view it at 365education.weebly.com. You might also want to take a look at the Microsoft Educator Network, which has a searchable bank of lessons and resources that you can use in your classroom. You can also check out my Choose Your Own OneNote Adventure Stories learning activity that was added last month.