1. Regularly back up your files onto an external hard drive or cloud storage (i.e. Dropbox, Google Drive, etc.).
2. Delete any unnecessary or duplicate files or folders.
3. Utilize compression software to reduce file size (i.e. WinZip, RAR, etc.).
4. Uninstall any unused programs or applications that are taking up unnecessary space.
5. Add an additional hard drive for extra storage capacity.