email from postfix going in spam/junk in gmail/outlook inbox

[m.islam...@googlemail.com]

Hi
I have postfix email server in ubuntu14.04 installed and configured. Emails from this land in spam for gmail and outlook. I have been assigned this task to check.
I have seen there is no SPF, Reverse lookup, and DKIM. I have installed and made necessary changes in server and DNS records. while I send email to: check...@verifier.port25.com I got this reply
======================
Summary of Results
SPF check: pass
DomainKeys check: neutral
DKIM check: pass
SpamAssassin check: ham

Still email going to spam. Could anyone please help what I missed?

[Burkhard Ott]

Check the header tag in the email.

[m.islam...@googlemail.com]

How would I check this, I dont have any file at /etc/postfix/header_checks

Sorry I am new bee in postfix.

[d.agosti...@gmail.com]

Hi

Is your public ip adress trusted ?

If not you should add stuff like SPF.

Regards

Victor