Monitor Your Data Usage
Before you start trying to reduce your data usage you should first find out how your data is being used by your Android apps.
If you have Android 4.0 (ICS) + you phone has a built in app for this.
Go to Settings > Data Usage
Set the limit to 1.0GB and Set a warning slight below that (750MB) to warning if your getting near to the limit.
Set the Data usage Cycle so It lasts for the Duration of your Goodybag.
The app will also show how much data each app has used.
If you have an phone that only supports an older version of Android. Download 3G Watchdog from Google Play.
Only Update Apps Over Wifi
Apps are been update all the time and good to have lastest version.
Google Play can automatically update these apps. Unfortunately apps can have a large file size and use of a lot of data to download.
In the Setting of Google Play if you check "Update over Wi-Fi only" then it will only update when you are connected to Wifi and not use your network data.
Turn off Auto-Sync
Auto sync is indeed a nice feature of Android but you can save large amounts of data by turning it off. You can also disable background Data activity. Also remember to disable auto sync of few individual apps like Picasa and Facebook to save the bandwidth.
Do have your emails pushed to your phone? Unless you are expecting an important email turn Auto sync off and manual check your emails through out the day.
The Power Save Widget Provides a quick way toggle Auto sync on and off.
Widgets
Fancy Widgets that tell you the weather and up date the news look nice and might provide you with useful information but they use data. Does you need to your phone to tell you the weather every 10 mintues? If you have them consider removing them or changing the setting so they update less often
Use Opera Mini Browser
Browsing pages on Opera Mini reduces your data traffic to about 40%. As the browser uses powerful servers to compress data by up to 90% before sending it to your mobile the page are loaded at lightning fast speed and at the same time fight against high data usage.
Install Onavo Extend With Onavo Extend, engage in more app activities, photo sharing, web browsing and more on 3G without breaking your data cap. The app lets you compress your mobile data. It works similar to Opera mini by routing all your data through VPN. This mean not just your browsing is compressed but all your apps are too. The app claims to reduce you data usage by 80% It show how much data has been saved for each app you have used on your phone.
Unfortunately the is app is only available if you have Andriod 4.0 (ICS) +
Block Ads
If you have download and used any free apps you may have noticed that they are ad supported. Unfortunately these use a lot of data as they connect to the Internet to download the ads.
and your phone will not download these ads.
Use a Firewall
You can use a firewall to restrict certain apps to restrict the network. You can achieve this by DroidWall, a nifty and free android firewall, but its only available for if you have rooted phone. You can check a box to select if an app can connect to the network or (3G) or Wifi.
https://play.google.com/store/apps/details?id=com.
Reference