Requirements
Fluent in Back-End, Front-End and responsive design
Deep understanding of WordPress framework and architecture
Theme development and Plugin development on Wordpress
WordPress administration and maintenance
Teamwork (so he can work well with designers)
High attention to details (to be sure the output of his work has high quality)
Fluent in Wordpress, WooCommerce and its plugins
Fluent in HTML, CSS, Java script, php, jQuery