I have two website http://domain.ninexcel.com and http://www.ninexcel.com/. Both website have same content and same templates but I want to promote this domain
http://domain.ninexcel.com. How to resolve same duplicate issues and how to promote this. Currently this domain not showing on Google SERP.

If you won't redirect, you could possibly use canonical tag to point search engines to what you consider the real/best domain for he content