An action plan report for SEO

I have three small brochure-style websites which have been doing very badly with Google. I know that the company who created the sites used to use techniques to get high ranking on Google which have since been banned. What I would like is an action plan report detailing what you would recommend needs to be done to improve the sites google ranking and in particular, whether there is anything still in place that may be making Google downgrade the sites. Can you advise how long and how much such reports would take / cost please.