1.Turn off auto update:-This is one of the causes of data consumption in android mobile phones.Base on experience,i have not seen the usefulness of auto update.It doesn't add useful features other than taking up spaces in your internal storage.So,it is better to turn it off completely when in mobile data subscription.

2.Turn on background data restrictions:-When you turn this feature on,it will stop all the apps that are running on the background,except the app you open that will be running.

3.Don't download application with a large mb.