How can I keep messages I send from being classified as spam by others?

Here are a few things you can do to reduce the chance that mail you send will be categorized as spam by another system:
  1. If sending a text message, send as text only, not HTML.

  2. Do not send messages in all UPPERCASE.

  3. Be careful to avoid frequently using words or phrases commonly used by spammers (ie. make money quick, viagra, lose weight, buy cheap ...)

  4. Do not use wallpaper (special backgrounds), HTML signature blocks, or rich text icons within your e-mail messages. Frequently anti-spam software will see these as spam-like, and increase the spam rating of your message.

  5. Be aware of the kinds of tests that are applied to classify spam. A good source is the SpamAssassin test set.

  6. Never forward unsolicited mail to others.