Seo is a is a complex subject, but it ties in with the objectives.
Typically, one might accurately surmise that SEO is about increasing traffic to the website. 
Perhaps the most Important aspect of SEO is to establish what the business objectives and goals are.
From this point an SEO strategy can be established.
It may be for an existing website, the recommendations  drawn from a site SEO analysis may suggest structural amendments to the website or  even a fresh start. 
For a new website the SEO will have an influence on the design process.
Competitor analysis is undertaken, after all, they will be assessing you and companies change, merge and engage marketeers, so it is important to keep an awareness.
The second key aspect of the SEO strategy is to measure the process, the traffic and study  customer behaviour on the website.
The recording of  factors affecting the performance of the site is important.
Memories are short, and external factors such as weather, economic fluctuations, or the demise of a key competitor are as important to record as physical changes to the site, or the planned implementation of SEO practices.
A year later, the first trend analysis can be compared to the previous year with these factors taken into account.
Keeping in mind what the objectives are the overall strategy may include pay per click campaigns,  social media and local on the ground promotional activity.
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