Well first thing is to ask yourself these questions
- Who is my target audience? (Marketing 101 but it's amazing how many people skip this)
- What am I relevant to? (How relevant is your site content within industry or niche?)
- What problems am I trying to solve? (Every search query generated is someone looking for a solution to a problem)
- Does my site require localization? (if the site has any relevance to location that will play a big part in your Optimization strategy)
- What are my goals and KPI's? (Knowing what the "R" is in "ROI" for you site and or campaign is essential to planning for it's success.)
- Who are my Organic competitors? What are they targeting? (Knowing the competitive landscape in and out will give you a clear indication of routes currently explored my others in your space and will help you determine you KW path)
- Who are my Paid competitors? What are they targeting? (Don't forget to research the paid media targets & spend of your competitors. PPC will give you great insights into high converting terms and will provide you with a great snapshot of you competitors mindsets when placed side by side their organic plans.)
- And last but not least, Who do I want to rank for and where? (Here is the question that every optimization guru needs to ask themselves when trying to "rank". Searches are tailored now to an individual and results can and will be scewed by a searchers location,social interactions,search history and more. So understanding the who, what, why and where is essential to your long term sustainability and ultimate success)
Finally let say that while keywords are still a relevant piece of planning your campaign and should get some focused attention, they are losing relevance by the minute as Google has gone almost completely to not provided now anyway. Also you don't want to get into the habit of having your reporting be Keyword focused. Start researching new and exciting metrics that can show real return. SEO's trying to hold onto reporting heavily on Keywords will be out a job soon.
So focus should be put into planning a relevant, valuable, content rich website that takes it's intended audience on a specific journey resulting in whatever your "R" is. Focus on your audience and being hyper relevant with solid best practices and you will be fine.