phpmailer php header email垃圾邮件

I am running into a problem while sending out emails from the system and the problem is that the email gets delivered to the spam box in gmail/yahoo/hotmail. I am posting here, after doing my bit of homework, and have already validated and checked the SPF settings, Reverse DNS settings(was pointing elsewhere, and made the change this morning about 5 hours ago). The RDNS check now says the mapping is perfect. Yet no luck. Mails are going to spambox. What could be the problem?I am running into a problem while sending out e