If you're thinking of working as a teacher, especially an EFL/ESL teacher, this is what I've learned after six years.
Always keep a set of spare lessons ready to go, because if an activity fails or it turns out the class already know what you're teaching, you'll need something to replace it with. And if that fails, something else again.
Students can spot a fake.
Whether it's a fake smile, fake enthusiasm or confidence, fake anger or patience...or fake knowledge of the subject, you won't fool them.
If they don't like you, you may as well not try to teach them. If they do, and they still make no progress, you're a lousy teacher.
The good news is: Students who like their teachers tend to believe they've been taught a lot and well - even if they've made no progress at all.
You control what you put in, not what they get out.
Saying "I taught them X" and saying "They learned X" are two completely different statements.
You might find yourself teaching one bit of vocabulary three times, but they only learn it when you say it casually while explaining something else. Whatever you think you're teaching, you're teaching other things too.
Many students just don't want to learn.
It's not your job to make them.
Some want to have learned, but don't want to go through the process. Some are in your class because their parents or employers want them there. And some joined in a moment of madness.
Whatever the reason, you are a resource for those who want to use it, not a drill sargeant.
You are sometimes a counsellor.
But you are not a mother. Or a friend.
Everyone has off-days.
If your student is ill, exhausted, depressed, hungover or stoned, let them take it easy.
If that involves letting them sleep at the back while you revise with their classmates, fine. If it involves the class watching a video - for which you have prepared a vocabulary list, in case the boss looks in - no problem.
Are you a people person?
Be prepared to become fond of your students, tolerant of your colleagues, and spittingly hateful of your boss.
If you have some other configuration of emotions, you're in the wrong job.
Love - don't do it.
We've all seen it happen - sex and/or romance between students and teachers.
Usually it's the student's idea, and it usually doesn't last long. But it takes a degree of emotional maturity from all parties to deal with the aftermath.
Employers, the general public and some colleagues do not have emotional maturity, so just make sure they don't find out about it.
Some slopes are slippery.
Alcohol is the drug of choice among teachers. I don't know why - with the hours and workload, I'd have thought amphetamines. If you don't have a colleague with incipient alcoholism...well, you probably do, but don't know about it yet.
You have a certain amount of energy every day. If you can't function without a cup of coffee between each lesson, you have exceeded this amount. This is not heroically giving of yourself, or going above and beyond the call of duty, nor is it everyone admiring you for having boundless energy, This is called running on empty until you crash.
After five years it's called Burnout.
You can't beat the clock.
You are not paid to teach an hour of english. You are paid to be available and ready between (say) 7pm and 8pm. If the student turns up at 7:30, they get half an hour, and they pay the full amount. If they don't turn up at all, and don't have a good reason, they're still contracted to pay.
Make sure this is crystal clear before the first lesson.
The other side is that you're paid to teach the full hour, even if you've finished after 45 minutes. Take up the time with practice, conversation, or games - what seems like ways to fill time can be the most useful part of the lesson, though you can't predict whether it will.
What they need isn't what they want.
Most students want to learn facts, not a skill. And those who don't generally want the skill and are impatient with facts. The latter are the one's who'll get good at the language, but actually they need both.
Teaching grammar is out of fashion, but without it all you can teach is cliched conversation - or the dictionary.
When a measure becomes a target, it ceases to measure.
You can teach students the language, or how to pass the exam. Exams don't test for ability in the subject, they test for memory of the syllabus.
This is why, whatever mark they got in the exam which ascertained their level, and thus put them in the class of that level - your class - a large minority will be a lot better or worse than their grade suggests. If you're lucky, this means you'll get one or two very able students who can help teach the others.
Teach what you know.
Use your regional accent, your vocabulary, your habits of speech. Not those of the textbook writers, and not those of whichever prestige group the students regard as 'standard'.
You can teach about how other people speak to some extent, but if you try to teach someone else's dialect, you'll get it wrong.
Find some common ground.
Bored teacher + Interested class = Bored class
Interested teacher + Bored class = Nothing learned
Bored teacher + Bored class = Even more bored teacher and class
Interested teacher + Interested class = Progress
Teach what you care about, provided they like it too.
A school is a business, not a service.
Student fees are the school's source of income - from a business point of view, the actual students are an inconvenience. To the owner, teachers are a necessary evil, not what makes a school possible, and providing resources is a drain on funds.
None of the methods work.
And some of them don't even exist.
The Callan method consists entirely of reciting question and answer pairs like: "Is a banana a vegetable? No, a banana is not a vegetable, but a cabbage is". Suggestopedia in practice means "do whatever you think makes students feel unpressured". Total Physical Response is "mime the words as you say them".
The "communicative" method is simply "get students talking as much as possible, and don't teach grammar". There is no method, just some vague aims. The reasons behind the aims are (1) practice is good and (2) teachers don't know grammar.
You don't need to know what the letters mean.
IELTS, TOEFL, iBT, NNS, VESL, ETS, CAL/CALL....
Usually they mean something that doesn't need an abbreviation, eg. Computer Assisted Learning, Non-Native Speakers, Educational Testing Service.
Otherwise, knowing what the letters stand for doesn't actually tell you anything, eg. Test Of English as a Foreign Language, International English Language Testing System. Almost no one who teaches them knows, and it doesn't help if they do.
There are sometimes hairline differences between TEFL (Teaching English as a Foreign Language), TESOL (Teaching English to Speakers of Other Languages), TESL (Teaching English as a Second Language) and other names for the same job. But I've never known them to make a practical difference in the classroom.
Most of the textbooks are rubbish.
They're not just boring, badly planned and badly written. Often they're just plain wrong.
Don't be afraid to openly disagree with the book in front of the class - so long as you can give a good reason why. And if you later find you're wrong, admit that too.
Use and develop your own materials if possible.
When you do use textbooks, quality beats quantity - one or two good ones are a blessing - 20 bad ones are a curse. If you find just one that's great, use the hell out of it, and get to know it backwards.
Silence is not bad.
If you need to stop and think, stop and think. Though if you need to think for more than 30 seconds, you probably won't find the answer after a minute.
If a student needs to pause while remembering a word or working out a spelling, saying something encouraging to fill the awkward silence will only distract them.
Know your roles. The real ones.
All the managing that needs to be done, is best done by teachers. All the administration that needs to be done, is best done by the secretary. All the provisioning that needs to be done, is best done by the owner.
Secretaries doing management, teachers doing admin, owners trying to teach - all recepies for disaster.
Teaching EFL is a way to see the world, not to make money. Training people who want to be teachers is the reverse.
Most schools run on a shoestring budget. Most go bankrupt - several times.
As with every other profession, incompetence is the norm.
Saul Alinsky was right. If it's no fun at all, you're doing it wrong.
Most advice is wrong.