Hi
Use wifi.
Don't watch hd video on mobile data.
Streaming will use lots of mb
Looking at picture rich web pages use more data.
Tethering uses more data.
When at home or in a place offering wifi turn off mobile data as some phones auto switch to mobile data when the phone goes to sleep.
Online gaming uses lots of data.
E mail with attachments use more too.
Having e mail set to push instead of fetch uses more data.
