Follow these steps
1
Open Settings > System > Storage and review Temporary files.
2
Select safe temporary categories, but review Downloads before deleting anything.
3
Empty Recycle Bin after checking that you do not need its files.
4
Uninstall unused apps from Settings > Apps.
5
Move large videos and photos to external or cloud storage.
6
Use Disk Cleanup > Clean up system files for old update files.