Back up your iPhone
Update iOS
Delete unused apps
Remove old photos and videos
Clear Safari history and website data
Delete large message attachments
Remove downloaded files
Empty the Recently Deleted album
Offload unused apps
Clear app caches where available
Delete old podcasts, music, and downloads
Review and remove duplicate contacts
Organize and delete old notes
Remove unused widgets and home screen pages
Turn off unnecessary background app refresh
Review storage in Settings
Restart your iPhone
Reset network settings if needed
Restore from backup if the device is still cluttered