Reducing the amount of spam you receive can be a tricky thing. There is no one way to reduce the amount of spam that you receive, but you can start with the following:

• Make sure that you have Spam Filtering turned on and configured correctly (see FAQ below on changing your Spam Filter settings).
• Don’t enter your email address into a website that you don’t trust. You may want to set up a separate account under your domain specifically for this use, so that you don’t get as much spam into your “main” mailbox.
• Don’t use a catch-all alias.

Also see the article on What can I do to decrease the amount of Spam I receive?