Communicative Language approach and task based Teaching . But sometimes with a class of low achievers who prefer repetition I use TPR= Total Physical Respond and GTM = Grammar Translation Method .
This isn’t a question that can be answered easily. Every learner and learning objective is so unique that I use a mix of methods. The ‘methods era’ has long since gone so we now talk about ‘approaches’. I try to use my experience to guide me but overall, I try to provide a rich language learning experience.
Fully agree with Tyrone Bishop, it is not an easy question to answer. Methods of teaching may vary significantly, depending on the age, level of proficiency, aims and needs of learners. If you teach children, games and activities can help a lot. If you teach business people, the communicative approach can help them develop their speaking skills as, most probably, they need to be able to communicate successfully. If you teach academic students who need to be able to write decent essays and assignments, the task-based approach and some other methods can give them the chance to improve their grammar and writing skills. What works best, in my opinion, is to know your students, their needs, aims and reasons for learning English as L2 and based on that, to tailor their syllabus and materials accordingly, so that you can meet most of their needs and expectations, and you can help them be successful in their learning. Just like there isn't ONE perfect textbook to teach English to everyone, there isn't one perfect method or approach of teaching which works equally well for all the learners.
Often this creation of 'methodological silos' is not helpful.
A hybrid of approaches might be the best way forward - as previous scholars have commented - it all depends on the needs of the stakeholders (learners, teachers, principle, parents, school, government policy).
It also depends on one's philosophy and how one views teaching and learning.
Well I join my voice to my colleagues, teaching a foreign language is not an easy task because of several factors, the context and the culture of the learners, their background knowledge, as well as their learning styles and differences. So, personally I opt for an eclectic style to cope with such differences and achieve my objectives.
"Low achievers" taught "grammar translation method". This is ridiculous, on the one hand, but understandable, on the other. Why? It is ridiculous because all adults (not only low achievers) will never acquire a good command of English without learning grammar! (I belong to those people who share this conviction.) On the other hand, it is understandable because in certain areas English grammars lag tragically behind modern linguistic research! One such area is compositional aspect (CA), something I have taught for decades (I do not teach any more, I am retired - but continue to do research). A colleague teaching English and linguistics (including CA) to university students submitted a paper on CA to a ELT journal and was astounded to realize that CA there was a ... terra incognita. Ridiculous - in view of the fact that CA was discovered half a century ago (1972, by Henk Verkuyl) and today there are hundreds of publications about it. (Whether most researchers handle CA correctly is another matter ...) What is CA? CA, a very complex phenomenon, explained in the simplest way possible, is such a thing that when you use articles you produce a perfective situation: "The/a tourist visited a/the castle". When you use the zero article, you produce an imperfective situation: "Tourists visited the castle"; "The tourist visited castles"; "Tourists visited castles". This is A FUNDAMENTAL FACT of English grammar, otherwise well-known to serious linguists - but totally absent in English grammars! Even in the largest and most comprehensive ones! It is NOT absent in my own English grammar (you can see it in my profile) but this does not make much of a difference. Bottom line: how can English grammar be taught effectively if a hugely important and fundamental fact is absent, unrecognized, misunderstood, ignored, in almost all English grammars published around the world?
The answer depends on many factors, among them the situational factors, facilities, and language learners. One particular method is not a good recipe for all tastes, no matter how comprehensive the method is. The teaching method should be localized and consider both psychological and social aspects of learning. For example, in a crowded class where 50 learners are present it is really hard to conduct communicative drills. Or where there is no facility in class to teach materials through PowerPoint, etc. The teacher should consider many factors while s/he is going to teach language classes. Kumaravadivelu's articles about Post-method era are very thought-provoking regarding the question you have raised here.
Grammar has been referred too much and too long as back bone to language learning. I scarcely teach nowadays. I simply recommend it for self instruction as it serve for a pair of scraches to some one wha met with a walking accident. As language learning aims at adopting and adapting the target language, I focus on language use-oriented models. We are experiencing the pragmatic approach to language teaching/learning to which we link the language access theory, which increase language/discourse awareness, the background to language/understanding. In short our teaching is developed on language use (learners' actual need) and language/discopurse awareness increase and discourse understanding.
In fact teaching English as a foreign language is challenging. Therefore, the teacher has to be eclectic in order to achieve his objectives. Moreover, he has to motivate his learners to be more responsible of their own learning because of the shift to learner centeredness which has changed the learner’s role to be more motivated and independent.