Here some amazing tips that i just read at http://spamcheck.sitesell.com/
With this tool you can see how likely your e-mail will be labeled as spam and how to avoid that.
Positive Things to Do and Say
... and a Very Special Thing NOT to Do!
Avoid any of the "telltale" triggers that might label your mailing as spam. Some of the most obvious negatives to avoid in your e-mails...
* The excessive use of ALL CAPS in the subject line and message body of your e-mail.
* The use of trigger words like "free" (used alone, or in combination with any number of words like "trial," "money," "quote," "sample," "membership," "access," and so on), "sex," "XXX," "spam," "$$$," "checks," "money orders," "extra income," "as seen on TV," and so on. Even using seemingly harmless words like "search engine listings," "cable converter", and "reverses aging" will penalize your e-mail, so you must be exceptionally vigilant in the analysis of your SpamCheck report.
* The excessive use of punctuation "!!!"
... and finally, a very special thing NOT to do...
* If you think of using a trick to avoid detection (like putting a * in certain words to disguise them or adding 50 spaces in your subject to push a code out of sight), it's only a matter of time until you are ESPECIALLY determined to be a spammer. Because "normal business people" don't use tricks -- they just do business.
On the other hand, there are certain elements of an e-mail that qualify it as being "bona fide" correspondence. With that said...
Here are some tips for staying on the "good" side of the various spam checkers, filters, etc. that stand between your e-mail and your reader's INBOX. Use as many of these "good triggers" as possible, to prove that yours is a real, justifiable mailing...
* Use of the words "news", "newsletter", or "list" in your subject line
* Indication of publishing frequency in the subject line -- weekly, daily, monthly
* Inclusion of date of newsletter in the subject
* Inclusion of the issue number in the subject line
* Make sure your newsletter has some substance -- when was the last time you saw spam that had more than a few lines of text?
Above and beyond that, use your own common sense. You know what spam looks like -- do not make your e-zine look like spam. And you know what a "VALID, GOOD" e-zine looks like -- that should be your role model! And especially...
... NO TRICKS. Just do your business and keep it real.