Every now and then, such as when you're taking a flight, you need to keep looking up the same information on your phone. If that information is static, and not especially private, you could take a screengrab and make it your lock screen. Then it's like a low-tech widget that won't change on you at an inconvenient moment.
Screenshot: Lucasfilm Ltd.
If your phone's clock and notifications get in the way, you could throw all the info into your note-taking app, add blank space at the top, and screengrab that. Sometimes this process is worth it; sometimes it isn't.
Other things you could put on your lock screen: Driving directions; the train map in an unfamiliar city; emergency info; babysitting instructions.
It's always a good idea to take a screenshot of your mobile boarding pass, in case your browser or mail app doesn't work properly at the gate. But don't share your boarding pass online, where someone could grab personal information such as your frequent flyer number.
Thank you to reader Zambah for this tip!