Clutterdiet is a very handy web site and Youtube channel that provide useful information on cluttering and organizing. She covers mostly things for home and business, she also offers some computer-related topics such as this one.
Email can be overwhelming with the amount of Spam (junk email) and advertising. Unsubscribe or send to your SPAM folder (this will vary how to do this depending on your email service). Use folders to sort your saved emails.