There is not a single method or ideal if the students are in a formal educational setting. I recommend to adopt a method, but it should be used some technics to improve the results. Soon a repetitive method gets boring so it is better to change a little and later on be back to the backbone of the course.
Like Naom Chomsky said learn a language like you learned your mother tongue through the immersion method. The best way is to live in the country where the language is spoken
Noam Chomsky is not only the biggest linguists ever lived, he is also one of the greatest thinkers of all times. But I don't think that he still would repeat that a foreign language should be learned as a native language. An adult has a complete diffrrent way to.learn things that a child may use. And the existence of a mother language makes a whole difference as your brain has already internalized a language code different from the one the person is willing to learn.
Language start with our arrival of on this earth by listening to the crying sound & the first loving expression comes out becoming the learning part of the language . With the growing period of the child he learns the language of his mother tongue where he may not find any difficulties or understanding his own mother tongue. In case of the learning the other languages in the line with his study or with interest or hobbies we have our devices of the standard books & the help of electronic media .
I would not say that learning other languages comes easy to me, but I have found personally that being immersed in a culture is the most important thing. It is only in this position that one can understand the idiosyncracies, colloquialisms and how meaning is made differently to one's own language. It also affords one the situation to practise. Learning by rote on the contrary is of course not a pedagogically sound method on its own. The student may well learn the sounds and the superficial meaning, but they are left devoid of the feeling of the words, the beauty of a language: What Hopkins the poet might have called the word's 'inscape'.