You might start your quest for best WordPress SEO by looking at the numerous WordPress SEO Plugins available. You will see lots of articles and posts reviewing these and producing top tens. You can also find articles giving the author's views on the essential plugins for anyone serious about SEO.
Whilst I agree that there are many beneficial plugins (and they should be used) it is a mistake to think that they will by themselves give you best WordPress SEO. It is better to think of them as fine tuning your WordPress site to make it as search engine friendly as possible but they won't turn round a site with poor basic SEO.
The biggest mistake you can make with SEO is to choose the wrong keywords. For the average webmaster getting a high ranking for highly competitive keywords will be very difficult if not, for practical purposes, impossible. It is therefore vital that you find less competitive keywords, but still with a good search volume, at the outset. It is always tempting to rush this stage but if you get it wrong it could well be that all your other SEO activities are a waste of time.
The other key requirement for best WordPress SEO is good content. Your content should be unique, of value to visitors and should be updated/added to frequently. Each page/post should be targeted at a keyword which should be used throughout the text and in various tags. You should understand how to write in a search engine friendly way and run through a checklist before you publish a page/post to ensure it is done properly. Best WordPress SEO is not trying to manipulate or deceive the search engines in any way it is simply writing your content in a way that enables the search engines to understand the relevancy of it.
So, if you have good keywords and good content you can start to achieve best WordPress SEO by installing some plugins to address the following:
* Titles - Control format of titles (in browser title bar and search engine results).
* Duplicate Content - No index duplicate content.
* Links - Automatically add internal and external links.
* Canonical URLs - Helps enforce chosen URL format (e.g. use of WWW or not).
* URL shortening - Remove common words from URLs.
* Sitemap - Make it easy for the search engines to find and index content.
* Monitor for Errors - Report broken links and 404 errors.
* Caching - Make the site load faster (good for SEO).
The above is not a complete list as there are many more things you can do to fine tune your best WordPress SEO. One SEO plugin I would mention specifically is SEOPressor which is one of my favourites.