Blocking spam is a balancing act. If you set the filtering level too low, your inbox might be overflowing with junk mail. Bump up the restrictions, and you run the risk of missing out on important messages.

One way to combat this is to set up what’s known as whitelists and blacklists. A whitelist is made up of email addresses that have your approval. A blacklist is just like it sounds: The email addresses that you want barred are not allowed to be delivered into your mailbox. You can tell your email provider or Internet service provider (ISP) who you want to receive email from and who you definitely don't want messages from directly by contacting their customer service office.

A second (and sometimes easier) way is to use the tools that you may already have in your email program or Internet filtering software to create your own whitelists and blacklists.