My accent and conversational ability in English is presently terrible. What is the best way to reach fluency?

I have no problem expatiating scientific jargon but fail at the rich palette of modern day English. I understand that fluency is a worthy objective, but I may need to set achievable intermediate objectives to reach my goal.

Generally I want something without too many 'additional elements' embedded into the accent. My main goal is developing an accent that facilitates communication with a wide group of English-speaking people as possible.

I work with a diverse group from different countries. Possibly looking for something without regional elements, which may hinder being understood by people who are unfamiliar particular region.