Once are generally done with all this, the next step will be to ask each SEO company to present the work status and ratings off of the previous companies.
The success of a SEO process depends greatly on the backlinks. You just need keep in mind to ask lots of questions. https://www.youtube.com/playlist?list=PLbZg6jL4FgfAS0TjMKfQ3hKiYOikfzmuE