It is always a big job to keep enough free storage space on our smartphones. We have taken thousands of photos, loaded hundreds of songs, and installed dozens of apps on our phone. And once the nightmare will popup “not enough free space.” And its not a good idea tostart randomly deleting files. See how simply Raymond Calbay wrote on htc blog.
First, you need to review your phone’s total storage and determine how much is still available. You can do this by going to Settings > Storage which will display the Internal Storage (usually reserved for apps) and Phone Storage (where your media files, downloads and docs are stored). Under Internal Storage you can tap “Apps” to see the storage requirements for each of the apps on your phone.
Once you know what is taking up space on your phone, you can take a few simple steps to free-up storage:
Save your files/photos to online storage automatically
Photos, videos and docs on the phone take up a lot of storage space. To reduce the impact on your storage space, you can set your phone to automatically upload photos to online storage services like Dropbox, google drive, Flickr etc. with upload schedule and privacy level. If you prefer to use Dropbox or Google+, you can choose to have files instantly uploaded as well.
Its a good idea to move photos and videos to online albums
Open your gallery and simply select the photos/albums and tap on "share", which will popup the enabled Sharing services. Click next, You are Done !. Once the upload is complete, you can delete the copy on your phone.
Unused apps; remove it, we don't need that
For general cleanup purposes, go to Settings > Storage, and then tap “Make more space.” Your phone will guide you through the process to clear the app cache. After this is cleared you will have an option to select any apps you want to uninstall. (Pre-loaded apps cannot be uninstalled, but can be disabled in Settings > Apps > All). Need the removed apps again ?; no worries, its always available in play store.
Also remove the temporary files/caches like browser files, maps, or music, by selecting “Make more space” under the Phone Storage heading.
Sync your files with your computer
Sync/move your confidential files on your phone to your computer, using your USB cable and select "Disk Mode / Disk when plug your phone into your computer. Now your phone will be recognized as a removable drive, allowing you to access the file storage – which could either be the built-in memory or a storage card (if supported).
From your computer, look through your phone’s storage content and manually cut-and-paste the files you want to move. For instance, if you want to save your text messages for future reference, just go to Messages > Menu, and then tap “Back up SMS.” Once backed up, this file can be restored to the Messages app if needed.
Thanks Raymond for a nice note on this.
Courtesy : htc Blog