SEO for Website (On-Page and Off)

I have a website I need SEO work done on. This will be on-page (the content) as well as off-page (meta title, keywords, description). This site already has a decent amount of traffic and the client would like to see better results. I will require a detailed list of keywords as well as the scope of work to be completed (time and cost). This is a WordPress site. I will provide more details once the job is awarded. Thank you!