When it comes to vocabulary learning and teaching in EFL settings, I am afraid to say that there is no single best approach or method. As a high school teacher of eighteen years, I have personally come to use the following three tried-and-true methods: teaching collocations, synonyms, and, above all, metaphors.
Metaphors have been effective in organizing what my students have already known. I do believe that teaching a series of expressions and applying an explicit label of metaphor on them would help learners see the English vocabulary in a new and clearer perspective.
A "Lakoff-Johnson" type of approach to vocabulary teaching is well worth a try. The Macmillan English Dictionary for Advanced Learners has a unique feature to enlighten dozens of conceptual metaphors in English language. I find this dictionary very helpful to both teachers and learners. Does anyone want to back me up?