The phrase "effective manner" means doing something well and successfully. It refers to performing tasks or actions in a way that achieves desired results efficiently. Full definition
The resume should list all the relevant educational and professional details in effective manner that can catch the eye of the employer. (sampletemplates.org)
The department serves quality meals to the greatest number of students in the most cost effective manner possible. (mps.milwaukee.k12.wi.us)
You need to understand what formats work (or don't), the type of information readers expect to see and the most effective manner in which to highlight accomplishments. (executiveresumepro.com)