Delete any files that are not absolutely necessary.
Image files take up huge amounts of space.
If you have images that you need to keep, it is best to store them in a .jpg compressed image format, which is smaller than a .bmp or .gif. Sound files can take up a lot of space. Look for files with the extensions .wav or .mid, using the Find command as mentioned above. Holiday greeting programs are often huge. Please, delete them after the holidays are over.