Assuming this is an existing website, first I would take a moment to determine what had been done up till now; so onpage, backlinks, traffic, etc.; Second I would evaluate the UX making sure things flow for when the user is interacting and not causing a high bounce rate or other issues; Third I would analyze the competition as to determine an appropriate approach for the client to move forward on. With us we offer our advice as a consult and/or service, where they can then take the info somewhere else if they like, or have us perform the optimizations. Additionally we look at this a bit more in depth when in a real scenario, we try to bring a whole picture approach bringing in brand identity, development, and technology to aid in getting the desired results. Hope this helps with whatever you are looking for.
Todd Richard