Linux Server - DKIM - Email Marketing

I am looking for a long term relationship for server support, with a few hours of consultancy per month. To start, I will need help checking if my DKIM is set right (getting message poor from gmail) and help me with configurations that help deliverability. Second task may be set a ip rotation, but this is still to be decided. I have a CRM website that delivers email marketing and right now, I am considering to separate the email marketing to a dedicated server, so I gonna need help with that too.