more effectively

most effectively

trees can be used effectively by not cutting them down

Well you obviously were NOT communicating effectively. To communicate effectively you need to have a good understanding of the language you are using to communicate with.

If you had a good understanding of English you would know that "communicating effectively to" is not correct English. If you were communicating effectively using English you would have asked "How do you know you were effectively communicating with other staff" as your question.

Evaporation is used effectively in an evaporation cooler.