Delete Your Old iPhone Backups
iCloud storage only offers 5GB of backup storage space. However, if your iPhone is plugged to a power source, connected to a Wi-Fi network and locked, it will automatically start backing up files which will then take up more space. You can free up some space by deleting old backups on your iCloud account.
- Launch your iPhone Settings App.
- Click on General > Storage & iCloud Usage > Manage Storage.
- If there are old iPhone 4 or iPhone 5 files that are still backed up in your iCloud account, click on them and tap on Delete Backup from the pop-up menu.
*You can upgrade your iCloud account for more storage space or connect to a computer with iTunes and perform regularly backups.
Stop iCloud Photo Library Service
To stop iCloud Photo Library service, go to settings > Photos & Camera and uncheck iCloud Photo Library. This will free up more space on the iCloud and phone too. Be sure to connect your iPhone to a computer or storage media and perform regular backups.
Avoid Keeping Both Regular and HD Photos in HDR Mode
Disable the "Keep Normal Photo" feature in “Settings > Photos & Camera" and just keep the HDR photos.
Save Larger Files to a Computer/External Drive
Long videos could easily eat up your iPhone's storage space. Export large media files to a PC/Mac.