You can look on YouTube for app reviews and "how to" videos. I learned a lot just by watching other people interact with their devices.
Check the permissions of apps you download. If something seems to seek more permissions than needed, you may not want to go that route.
Evernote is recommended above. I have no doubts that it works well, but read the fine print. Everything you put in Evernote becomes the property of Evernote. Including photos, contact infomation, etc. That bothers me.