You can improve accuracy of spam detection by training the spam filter on the e-mail messages that you have in your mailbox.
To improve accuracy of spam detection:
All e-mail messages you have in your mailbox are presented on the screen.
In most cases, you can tell if a message is spam by looking at its subject line and sender's name. If they do not give you any clue, try looking inside the message using your e-mail program or Webmail interface (Home > WebMail).
If you have accidentally made your spam filter learn a great number of spam e-mails as non-spam or vice versa, your spam filter will likely produce incorrect results. In this case, clear the spam filter's database and then repeat training.