When it comes to teaching languages,in this case teaching English,some perfect system would be a system where students are learning deeply and they are willing to exhibit their knowledge publicly.Also,all the individuals involved in the teaching process should really belive  in what they are doing and students should be at the center of learning.        

  Before deciding what teaching method or technique to use,the priority is on specifying teaching and learning goals and finding out what student's prior knowledge is because that is what conditions everything that follows.

In each group,with different ages and different levels,as much as possible needs to be found out about each student.As mentioned before,prior knowledge,their goals (purpose why they are in the classroom) and their personalities.To find out that,the use of sample inventories and questionnaires is always helpful.Of course there are many other ways but in my opinion these two are the best and the ones I would use.

 It is also very important to check all the affective factors that have influence on the process of learning (acquiring).Those are personality,motivation,environment and opportunity.

For a successful learning process it is important to follow the order of natural acquisition of L2: 1.listening; 2.speaking; 3.reading; 4.writing.

As I belive that most teaching methods have some good and some not that good principles,the key would be to combine principles of different methods.

It is essencial not to use L1 (mother tounge) in class as it slows the process of learning L2,in which case L2 can not be automatic.Another very important thing is to correct errors immediately before the student gets used to them as later it will be more difficult to correct it.

In the process of learning language some difficulties can show up that are related to interlanguage.Interlanguage is system we use until we become profisicient users of the TL.It referes to errors that can be made by simplification of structure of language,overgeneralisation (one rule applied to everything) and language transfer.

What areas of language should be emphasized,it is the best to decide after getting know the students goals.

Teacher roles':

-a guide

-a resource

-a controller/organizer

-a facilitator 

-a psychologist

-an authority

-an assessor

Students' roles:

-an imitator

-a communicator

-a self manager

-a passive learner/receiver

We need to have in mind that we are all different types of learners and there are different types of intelligence.That means that for different types of intelligence different types of activities should be used.It takes some time to find out that but one thing is sure,after we get to know our students better,we will be able to have a better influence on students' motivation.Motivation is the most important factor in language learning.Some people are very self motivated (intrinsic motivation) while on the other hand some people need to be pushed all the time by their teachers,parents or bosses (extrinstic motivation).Types of motivation depend on age,level or personality.We can motivate our students in many different ways.We  can find our their interests and change the materials if we see that the students are not interested or bored.Praising their performance when progress is obvious is always a good way to get our students motivated.To keep them involved,it is good to give them to choose different possible tasks,etc...

Assessment is the result of activity compared to objectivity.It is what the teacher sees so it needs to be specific,measurable,observable,achievable in relation to the lesson and of course it needs to be realistic.There  are different types of assessments and in my opionion the best ones are self assesment,assessment by others and fixed point assessment.I would use these 3 to see what my students have learned.

Teachers need to be adaptable because they will be exposed to different ages,leveles,goals and personalities,so the materials used in class will be different for each group of course.Teacher's materials can be authentic or adapted.

After we have found out goals,skills,prior knowledge and we get to know our students it is time to decide what teaching method or methods to use.As I have already mentioned,I wouldn't necessarily hold on to one method so my choice would be combining principles of different methods.

The Direct Method has many advantages.There is no use of mother tounge as it slows down the learning of the target language.The goal is not only to use TL but to think in TL .Oral skills are emphasized but it works on all 4 skills.Vocabulary is more important than grammar and new words are taught with demonstrating and using realia.Grammar is taught inductively.The Direct  Method has Situation-based organisation of syllabus that mean that content is focused on real or imaginary situations in which language occurs.

For beginners and young kids my choice would be The Total Physical Response method based on coordination of language and physical movements.It works on all 4 skills but listening is emphasized as the main hypothesis of TPR is that language is learned primarily by listening.Vocabulary and grammar structures are emphasized over other language areas.Althoug the grammar is not taught explicitly but it can be learnt from language input (listening).It is a very valuable way to learn specially difficult or idiomatic vocabulary,eg. phrasal verbs. Spoken language is emphasized over written language.This method uses a Sentance-based syllabus with grammatical and lexical criteria in selecting the teaching items.

Although Callan method  is in a way an aggressive method, for some groups (depending on student's goals)it could be used.If there is a group of students that want or need perfection in use of TL,accuracy would be more important than fluency or both would have the same importance.In that case this method would be my choice.It has  Structure-vocabulary based syllabus (question-answer form) and imediate correction of errors.Everything is taught through modelling and practices.The goal is to stimulate a student's memory with very dinamic classes.The emphasis is on grammar and pronuncation.

Finally,when we are aware of what teaching methods and principles are going to be used it is time for a lesson plan.The lesson plan for,let's say P3 level,would consist of 6-7 activities depending on our objectives.It is always good to start with a set of quick questions to activate the knowledge from classes before.These 6 activities would be 2 structure ones,2 vocabulary and 2 topics.The first structure activity would be about the passive voice (expressing emphasis and focusing on past and future tenses).The second structure activity compares active and passive voice (how to use it).The first vocabulary activity is to learn adjectives related to food and to use them in a sentence.The second vocabulary activity is to learn new vocabulary,for example about accounting and book keeping.Finally,the topics would be for students to practice conversation and fluency.The first one is to talk about the value of money and the second one is to explore new TL.