My SPF record seems to be passed but still going to spambox - spam-prevention

Question

I am sending email with swiftmailer, All of them goes to the spam folder, The SPF shows the status pass. what could be the changes i need to do to unspam it
Delivered-To: josemon.zixent#gmail.com
Received: by 10.107.191.131 with SMTP id p125csp117228iof;
Tue, 18 Oct 2016 22:20:57 -0700 (PDT)
X-Received: by 10.55.18.28 with SMTP id c28mr4620542qkh.125.1476854457365;
Tue, 18 Oct 2016 22:20:57 -0700 (PDT)
Return-Path: <tips#interviewtips.xyz>
Received: from interviewtips.xyz (li1017-172.members.linode.com. [45.33.71.172])
by mx.google.com with ESMTP id w74si23142432qkw.3.2016.10.18.22.20.57
for <josemon.zixent#gmail.com>;
Tue, 18 Oct 2016 22:20:57 -0700 (PDT)
Received-SPF: pass (google.com: domain of tips#interviewtips.xyz designates 45.33.71.172 as permitted sender) client-ip=45.33.71.172;
Authentication-Results: mx.google.com;
spf=pass (google.com: domain of tips#interviewtips.xyz designates 45.33.71.172 as permitted sender) smtp.mailfrom=tips#interviewtips.xyz
Received: by interviewtips.xyz (Postfix, from userid 1001) id B36DE817B9; Wed, 19 Oct 2016 05:20:54 +0000 (UTC)
To: josemon.zixent#gmail.com
Subject: [josemon.zixent] Is your Resume not getting shortlisted?
X-PHP-Originating-Script: 0:SimpleMailInvoker.php
Message-ID: <a6d39b3f95ee3608da294edc48eee3e7#interviewtips.xyz>
Date: Wed, 19 Oct 2016 05:20:54 +0000
From: tips#interviewtips.xyz
MIME-Version: 1.0
Content-Type: multipart/alternative; boundary="_=_swift_v4_1476854454_e4fa42ac587c6d9e0a47f9b64d71b9ec_=_"
tips: tips#interviewtips.xyz
--_=_swift_v4_1476854454_e4fa42ac587c6d9e0a47f9b64d71b9ec_=_
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
--_=_swift_v4_1476851958_4161d478461e54e72c39c80d6e24bfa1_=_
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable

Answer 1

If you want your emails not to get in spam you need a few more things than just an SPF record. Specially when you are sending mails to Windows or Google you need to have a good reputation. They got spam filters wich will add you to the spam folder quickly if you have a small problem with your reputation.
Get some more information about the following protocols if you want to get a good repu:
SPF
DKIM
DMARC
PTR
There are a lot of domain checking tools you can find by googling.
I prefer this: http://mxtoolbox.com/domain/