Configure SMTP server using my email marketing scripts to avoid spam/junk

I am using a php bulk email marketing script on a dedicated server and I keep running into issues with campaigns always ending up in gmail's junk box.

As a programmer myself, i decided to go a different route, but the server side of things isn't my specialty : / but i've managed to get VERY close. I realized using my dedicated server to host a mass emailer is a ticking time bomb for getting my server IP blacklisted.. so I decided to invest in setting up a separate mail server. Long story short.. I assure you my mailing lists were legally obtained and i am not a spammer. I was having issues with getting the DKIM/SPF to verify from TXT records i setup via WHM DNS Zone Editor. I'd rather start fresh by using something dedicated to just my bulk email sending.

I was thinking about using Amazon's SES or ElasticMail.com as the mail server and routing it through my website that's hosted on my dedicated server. I'm open to alternative solutions if you have any recommendations.

The only issues I've been having getting the DKIM and SPF verified, which I believe is the issue with emails going to gmail's spam folders. This shouldn't be too difficult for someone thats done this before. If my domain name is the issue, I'll purchase a different one. I just need a mail server setup so that my email marketing website will stop ending up being flagged by gmail.

I've done numerous spam list checks and my domains being used are clean.
The scripts being used: http://www.mailwizz.com

You need to be experienced in SMTP mail servers (and getting sites to avoid spam flag), PHP, Code Igniter, debugging, and the ability to complete this relatively soon/quickly.