1. Remove things you no longer need on your Lumia Windows Phone 8, use the Storage Check application. Go to Settings > Storage check, swipe left, the screen will show you the amount of storage used by Apps, Downloaded Maps and Temporary files:
- Select details under Apps to find out what apps you have on your phone, consider uninstalling some of them to increase the space in your phone memory.
- Select maps under Maps, the screen will show you the maps you have downloaded to your phone. Long press an individual map to get an option to remove it, or delete all maps.
- Select clear under Temporary files to clean up the files that are safe to remove.
2. Delete browsing history, temporary files, cookies and saved passwords in Internet Explorer (Settings > applications > Internet Explorer > delete history).
3. Delete previous map searches and temporary files from your phone (Settings > applications > maps > delete history).
4. Delete Bing search history, including Bing Vision and Bing Music searches (Settings > applications > search > delete history).
5. Remove old Office documents on your phone: Press Start, swipe left, and select Office > places (locations) > phone. Long press any document and then select Delete.
6. Remove offline mixes from MixRadio: Press Start, swipe left, and select Nokia MixRadio > offline mixes. Long press any mix and then select Delete.
7. If you have a PC, connect your phone to a computer with a compatible USB cable. On your computer, use the Windows Explorer and browse to your phone to see a list of the folders: Documents, Music, Pictures, Ringtones, and Videos. Right-click the file you want to move, select Cut, right-click a location on your PC, and then select Paste.