-Before making any change make sure you add your site to both Google and Bing webmaster tools and submit your XML sitemap to them(if you have not done it yet).
-In this period a link building campaign targeting your naked domain is very useful.
– Yet you have a bigger fish to fry, the architecture of wordpress is also very important, for foundations follow whatever
Joost de Valk says.
– Get familiar with WordPress taxonomies, custom taxonomies and custom post types and use them effectively based on your objectives and content.
-For your new URLs as the best practice use Yoast SEO plugin and for Permanent links at WP setting chose the fourth option which is %postname% .
– At last submit your new XML sitemaps which are generated by Yoast’s plugin to the webmaster tools,
-After shifting to WP you have to report the 301 to Google webmaster tools, it’s very important to follow Google’s guideline on reporting 301.
I followed these steps in a similar issue and at the same time I needed to change my naked domain to another TLD, and I lost no pagerank or organic traffic.
P.S. : Non of my posts in this blog is written for article marketing and neither of the links are affiliated. What I write is what I know, think, feel, experience and like to share.