1. Monitor what's using your data
Chances are that your smartphone is almost always connected to the internet, be it over Wi-Fi or 3G/4G. Do you know what apps consume most of that data? If not, then try Android's built-in data usage monitor, available from the Settings menu, or just get an app for the job – Onavo Count or Traffic Monitor Plus. Keep an eye out for data-hogging apps.
2. Keep your storage space clean and tidy
It seems like the on-board storage space on smartphones is never enough. That's why moving your stuff – music, videos, apps – onto a microSD card is a good idea. Also, try to get rid of apps and games that you don't use since these occupy space as well. Just go to Settings > Apps and uninstall whatever software isn't needed. To get a better idea as to what files and folders really take up the most storage space, get DiskUsage from the Play Store. It represents visually each folder with a rectangle – the bigger the rectangle, the more space it occupies. Then just move or delete all the stuff you don't need using a file manager. ES File Explorer is one we'd recommend.
NOTE: Don't delete any files or folders unless you're absolutely sure they aren't in use by an app or the operating system!
3. Monitor what apps are loaded and running
When a smartphone is turned on, it loads a whole bunch of apps and services that run in the background. Most (if not all) of these are harmless, but others just sit there, taking up memory and keeping the CPU busy. Autorun Manager is one of the apps that can show you what software is loaded on start-up and what's running on your device. Feel free to disable or uninstall apps that you don't need.
4. Avoid suspicious ad-supported apps
We have nothing against ad-supported software, but some apps take that concept to the extreme, with ads being displayed on the notification bar. Some even add links to shady search engines to your home screen and suspicious bookmarks to the browser. These apps should be avoided since their ads consume data and battery life, not to mention that they might put your private information at risk. To see what ad-supported apps you have installed on your Android device, give Lookout Ad Network Detector a try.
5. Monitor apps' battery usage
There is a built-in battery monitoring tool in the Android operating system, accessible by going to Settings > Battery. Keep an eye out for apps that consume excessive amounts of power without being used that often.
6. Make parts of Google Maps available offline
In case you use Google Maps on a regular basis, you might want to save frequently viewed areas for offline use. That will save you data whenever Wi-Fi isn't available. To do that, open the menu in Google Maps, tap on "Make Avaliable Offline" and select the area you want to cache onto your device. Note that saved areas may be up to 100MB in size.
7. Monitor the permissions of installed apps
Do you know what kind of information your apps have access to? If not, Clueful Privacy Advisor is the app you should consider downloading. It scans your Android device for suspicious apps, including apps that may leak your passwords, phone number, and other sensitive data.
8. Know how to track a lost or stolen phone
In case you have not heard of these already, there are Android apps capable of tracking a lost or missing smartphone – apps like Lookout, which is also a good anti-virus tool, and Where's My Droid. Just make sure you have these installed and configured before actually losing your phone.
9. Automate your phone
Your phone is smart enough to mute itself while you're at work, to turn the Wi-Fi and 3G off at night, and to do all kinds of stuff automatically. you just need the right app for that – an app like AutomateIt, Tasker, or Phone Schedule, to name a few.
10. Try an alternative virtual keyboard
Not entirely happy with your smartphone's on-screen keyboard? Well, there's plenty of alternatives to try, including SwiftKey, TouchPal, Swype, and many more.
11. Get an SMS counter
Obviously, this tip is for people who don't have unlimited text messages included in their monthly plan. To them we recommend trying the SMS Counter app, which will keep count of both incoming and outgoing text messages.
12. Take over your notification light
In case you have a notification light on your phone, you may customize the alerts it displays using the Light Flow app. And in case you don't have one, make your camera's LED light flash at specific events with the Flash Notification app.
13. Cut the wires
There's this neat application called AirDroid, allowing one to manage their Android smartphone from a computer over Wi-Fi or 3G/4G connection. In other words, with this app you can access your phone from a PC and then copy files from and onto your smartphone, send text messages, install or uninstall apps, view photos, music, video files, and much more.