This is often a question that comes up too often and there are some simple things you can do to help. Your smartphone is like a small portable computer and requires some maintenance from time to time. Nothing overly complicated. This will work for anyone. I will also include some more advanced things that can be done further in the article.
One of the major things you do is to remove “uninstall” all these downloaded apps that you are really not using. Whether you know it or not, some of these applications often require processing time to either update, sync, interact with you in a manner that you’re not aware and it will take away the power your device has to complete another task when you want to use it.
To do so, you can go in the “app drawer”, find the “settings” icon and scroll down to “apps”. This should normally bring you to the download app section. You will be able to see what you’ve downloaded and from there be able to uninstall them. This method won’t allow you to remove system application and or apps installed by your carrier.
If you do want to take this a step forward you could swipe until you get “all apps” and then disable some of the applications you don’t need, mind you, you will not be able to use this method for all of the applications listed.
The other obvious thing that comes to my mind is cleaning up your storage device. You know all those, mp3’s, pictures, movies, empty folders? I think it’s time that you go through all of those and delete them. You could always use the cloud and send them there if you still need all of them. You could always turn on auto photo backup on your Dropbox or your Google+ account and let this sync and then delete.
I’d consider using a cleaning tool like; Clean Master, CCleaner (Crap Cleaner) which could make your life much easier instead of hunting this down on your own, this would do a much better job at it.
What about your application cached storage data? YUP! You’ve guessed it right, you Instagram app or your Facebook app keeps a cache size of what you’ve seen so that it doesn’t have to reload everything you’ve seen, making it faster to display the content. I would suggest not doing this too often personally. The above app I listed would actually take care of that for you.
If you want to really go to the extreme. Factory reset your phone. (YOU WILL LOSE EVERYTHING).
What if you’re an experienced Android user and would like to learn more about what you can do? If you’re already a root user, then you’ll know that the first thing I’ll suggest is to check out XDA developers and see about your specific device and look at the various “Kernels”. You can test them out for a few days and settle on the one you like. They will all be different and react differently so stick with something that works for you.
At this point you could also use a tool like Titanium backup to freeze the system apps you don’t want or even remove them; like the apps pre-installed by your carrier or manufacturer.Next step if you want to go all out. Try a custom ROM. What have you got to lose? Sometimes these roms will run even better than the actual stock rom you have from the company.