5. Save offline maps on Google Maps
In iOS, or Android, sign into your account in Google Maps, search for an area you want a map of, tap on the name of the location at the bottom of the screen, then tap the three menu dots in the upper right-hand corner of the screen, and select "Save offline map." You'll then be able to download and view this map offline by going to the menu, selecting "Your places," then "Offline maps," then "View and manage."
6. Check email on data, but wait for Wi-Fi to download attachments
No matter how important that PDF may be, we all know it's going to look like crap on your phone anyway.