Sub Domain SEO
SEO (Search engine optimization) of a sub-domain is like promoting a completely new web site.
The sub-domain stands by itself and needs its own SEO plan.
The sub-domain can be for another language: for example www.berkeley.edu and french.berkeley.edu
The sub-domain can be for another province / state: for example California traffic school and New York traffic school.
Each sub-domain is a world of it-self.
Make sure the UI (user interface) of the domain and subdomain are accessible and easy to navigate.
Looking for a deeper analysis of your web site? the Diagnostic Program can help you.