Improve Email Deliverability for our Web Applications

We have a suite of web applications. They mostly go into 2 categories: .NET and MS SQL hosted on dedicated VPS-es or PHP and MySQL hosted on shared hosting. Our applications send a lot of application specific emails to the users or external third parties which are part of our application workflows. For example, one of our websites takes applications for Master Programmes at a UK university and emails the referrers and asks them to go online and provide a reference for the students that applied. We have major problems with the delivery of our emails. Many of them would end up in the spam or junk folder or even bounce completely. We would like to review the way we are sending emails in our applications and improve dramatically the deliverability of our emails. We would like to work with a deliverability expert and setup a policy and best practice that we can then implement in all our current and future projects. Consequently, the job would be to review one or two of ours systems and prepare the full documentation with all the things we need to do and how. These are some of the things we would consider 1- Transactional SMTP Relay - Move all email traffic to reputable transactional SMTP relays (jango, sendgrid or mandrill). Which of them is better, do u have any other suggestions, how do we have to set them up using their API or via local host relay – what the ideal setup for such a gateway. We currently work with Jango on a few of our projects, but our understanding of how to use it it’s limited as we are developers. 2- Email Format Review – We would suggest to review the content, links, images, subject, sender etc and make sure our emails would pass Litmus tests and would be marked as perfectly clean. We are particularly interested on the sender email and how should that be setup in conjunction with our clients so that our emails look as legit. (PTR records etc) 3- Monitor Deliverability – How do we monitor deliverability, and make sure we get in the inbox? What tools can we use? How can we use Return Path or get other certifications etc? We would like to do a comprehensive audit of our current email delivery procedures and put together a state of the art method in place. We feel we’re primitive in the way we do our email delivery (simply using localhost in many cases) and this hurts our customer support. We need to work with a proven expert in this field and we would like to hear about your experiences. We don’t want to write a book, but the result of this engagement should be a very detailed and long email delivery procedure that will give us the certainty we do all that we can to land in that mailbox.