What is your SEO strategy when you start working for a new client?

What road map or strategy do you follow whenever you work for a new client to boost up their rankings.

For eg: If you have a client who runs a digital marketing company what would be your strategy to play differently in this huge industry. Since almost all of these SEO tactics have been somehow used by the people.

PS: My main motive in asking this question is to know how you guys plan and execute your SEO strategy as a result you get a lot of conversion.