Jill Berry, 55, taught from 1980 until 2010 and worked as a head of department, head of sixth form, deputy head and head at Dame Alice Harpur School in Bedford. She is a past president of the Girls’ Schools Association

Dear Jill

You have started keeping a diary, and you will continue to do this for many years. At the start of your career you often write about how exhausted you are. You find the job very tough at first. This is pre national curriculum and you feel alone in the classroom. You work very hard preparing lessons and materials, trying to come up with imaginative ways of inspiring students. This means you are knackered all the time. But you love working in your first school - a comprehensive - and love the staff and students.

You put in so many hours at work, but you have to stick with it. Remember, the job gets easier with experience and confidence. It will never be a doddle, but once you have a bank of resources and materials, you have a base of things to draw on.

You will be promoted, and enjoy each job more than the one before. You will eventually become a principal, which is the best job in the world. You have considered changing career, but as time goes on you will feel the pressure lifting. Later you will tell anyone who will listen how fantastic teaching is.

The amount of marking you have to do is immense. This is because you set so much written work. As time goes on, you will learn other ways of assessing children’s progress, so don’t worry too much about that.

I know you don’t always feel that grown up, but this will change. You will become a school leader and people will come to you for help: you will love this. The parameters of your job will widen and being a principal will feel like a huge privilege.

You will occasionally apply and be interviewed for jobs that you realise you don’t want. Luckily, you will not be offered them. Any teacher should have the guts to withdraw if this happens to them.

I would also advise you not to be so hard on yourself. You will work with lots of women and you will realise they judge themselves harshly. If you do something wrong, get over yourself and move on. If you go outside your comfort zone, things might go wrong.

You will learn from each experience, every mistake, and it will make you stronger. You’re going to have a fantastic career.

James Wilson, 28, has been a history teacher for six years and is assistant head of year at South Bromsgrove High School in the West Midlands

Dear James

You are taking on a challenge with your first job. The school (Archbishop Grimshaw School in Solihull, West Midlands, now called John Henry Newman Catholic College) was in special measures. But you have chosen to work there because you want a challenge, and you will find that the staff and students are amazing. After two years you will feel as though you can teach anywhere.

Don’t play it safe. It is easy just to apply to work in outstanding schools, but you will understand the power of education more if you teach in a challenging school. It will make you appreciate what children have to deal with outside school.

You grew up on a farm in rural Northumberland, where there was only one school in every 20 miles. You will be shocked by some of the things you see working in inner-city schools, and grateful for the love and care you had from your family.

You will find your niche as a teacher in the good relationships you have with children. This is so important. If 32 children in a class respect you, then your job is so much easier. The advice to trainee teachers is often “don’t smile until Christmas”. I would say smile every lesson: the children love it.

Keep believing in teamwork. See your role in the classroom as similar to that of the captain of the rugby team you play in. You will find an effective way to control behaviour and you won’t need to raise your voice. If you give children respect, they will also respect you.

It is great that you want to accept responsibility as a new teacher, alongside running rugby teams or volunteering for the Duke of Edinburgh’s Award to support young people’s personal development, but also learn how to say no. If you don’t, you will find you bite off more than you can chew, to the detriment of everything else.

Learn early on that every lesson plan is important, because it means you don’t have to do all that planning the following year. As a new teacher, you take for granted your reduced timetable, but spend more time observing other teachers because you won’t get the chance to do this again.

You will be lucky enough to be employed by some wonderful, pioneering schools - never apply for a job that you don’t want.

Jodie Johnson, 57, is an elementary school teacher in Vancouver, Canada. Many schools she has worked at have been in working-class areas with high immigrant and refugee populations and she is an English as a second language specialist teacher

Dear Jodie

In 1960 Mrs Quack, your kindergarten teacher, told your mother you were very helpful with others. You had tied the shoelaces of all those who could not, ensured that everyone had a snack and encouraged the children to play nicely. She was certain you would grow up to be a teacher. After first becoming a social worker, you went on to fulfil the destiny foretold by Mrs Quack.

Your first teaching job will be in an inner-city Vancouver school where the majority of the students are from South Asian families. During your first visit you will hear the chatter of incomprehensible languages and see a man dressed in a red and gold kurta, striding purposefully down the hallway en route to teach a Punjabi language class. You will know straight away that this is a place in which you would love to work.

Your first classroom will be cold and leaky. Your eager class of 20 students aged 10 to 12 will have recently arrived in Canada from all over the world and will all have stories to tell.

As such, your best lessons will be about topics that appeal to the students and to you. One of your greatest achievements will be how you find successful ways to integrate into your teaching your own passions: literature, cooking and nature.

Your finest moments will be when students exceed your expectations. For example, a lesson on poetry becomes a mass letter-writing exercise and children get replies from a Nobel Prize winner and the prime minister of Canada.

Students are the priority. They deserve a calm and caring environment in which to learn. So take a deep breath, leave problems outside your classroom, close your door on them and enjoy the time with your students.

It is imperative to prepare your lessons in advance and to have all your materials ready. Anticipate all the problems before the students enter the room. It will help you to have clearly outlined classroom rules and procedures for your students. Make your criteria simple and clear so that students are aware of the expectations for their behaviour and their work.

This job is all-consuming and never-ending. The work could consume all your evenings and weekends, but it shouldn’t. Eat well, exercise, laugh with friends and spend time doing things you love. It is important to lead a balanced life. Becoming involved in your local union will help you to see yourself as part of a greater collective. And you will love the opportunity to work with kind, caring, intelligent, creative, thoughtful, progressive people. There will barely be a day without laughter.

Lesley Ward, 58, taught at Intake Primary in Doncaster, for 35 years. She is a past president of the Association of Teachers and Lecturers union

Dear Lesley

You had an unconditional offer of a place at a teacher training college based on results in your O levels. Because of this you spent your time in sixth form in the pub. I would advise you to work harder in the sixth form and get good enough grades to go to university. You hated it at college, and you went only because you couldn’t get into the Wrens (Women’s Royal Naval Service) - although your parents were thrilled because you were the first person in the family to get into higher education.

Doing a degree would have allowed you to see a bit of the world, or teach history - a subject you enjoy - in a secondary school. But you will love primary teaching, particularly helping children learn to read, so don’t worry too much.

I know you are petrified at the start of your career. Your principal is a tough boss: you get sent home to change after wearing a sleeveless T-shirt to work in the hot summer of 1976. She tells you no teacher in her school should wear trousers at work either. Do the best you can, but if you feel you are unfairly treated, stick up for yourself without ranting or raving.

It will be worth it. Amazingly, because you will teach only at the one school, you will see three generations of the same family come through your classroom. You won’t be able to go to the shops without seeing someone you have taught. They will want to stop you and give you a hug. Your students will be from a proud former mining community, but the area will go into a slow decline and many of their parents will have known nothing but unemployment.

You will be very proud when you see the success of your students, including a double first at Oxford and a PhD in two cases. You will be just as proud of the student who becomes your beautician.

After finishing college, you will turn down the chance to work in London. Think again and don’t be frightened to do something different, even trying teaching in New Zealand or Australia. Don’t take the safe option.

Valerie Nicolson, 46, is the first female headteacher of Anderson High School in Lerwick, Shetland Islands. It is the biggest school on the islands and many students board during the week because they live too far away to travel daily

Dear Valerie

Your upbringing will have a big impact on your career. You were raised in a small farming community in Shetland, where you thoroughly enjoyed attending the local one-teacher primary school. At 14, you transferred to Anderson High School on Lerwick, Shetland’s main town. Given the relative remoteness of your home, you boarded in the school’s halls of residence for four years, travelling home at weekends. Experiencing this quality of education formed your expectations for what every child should gain from school.

Your first jobs are in and around Edinburgh. As a new teacher, you will experience kindness, fun and feel supported and valued. Later, you will become a principal teacher. You will teach in schools based in all sorts of communities, affluent and deprived.

Then, almost 20 years after leaving Anderson High, you will return there as headteacher. You will be a comparatively young leader, and the school’s first female principal, but the Shetland community will not be interested in this. What matters to them is how well you will serve the community.

Seek opportunities and make the most of them. You will benefit greatly from being involved in marking and setting examinations, being part of subject writing teams, accompanying students on trips, being on school committees, dancing at parties and singing in a pupil-staff choir. School life is so much more than the classroom. Your own learning will not stop. Even 10 years into the post, you will have the opportunity to be involved in national working groups.

There will be lots of striking memories in your career, but many of them will be the little things: the look on the face of a 16-year-old boy who has just secured an apprenticeship with a local builder or the emotion of being with the school netball team as they become Scottish Champions at Meadowbank Stadium in Edinburgh, having sailed overnight to Aberdeen to get there.

You will come to realise that although you don’t relish educational change, you can cope with it, manage it and make it your own. Draw on your early values to ensure that the children entrusted to you get the very best you can deliver.

Greg Ahlquist, 40, is New York State’s Teacher of the Year 2013, an honour awarded by the state’s education department. He teaches in a high school in Webster, a suburb of Rochester in upstate New York

Dear Greg

You have always wanted to teach; you just can’t decide whether it should be at university or high school. Your first job will be teaching Latin at a state university. You will then work in a children’s home and school for adolescent boys with severe social-emotional needs, as a classroom aide. The time with those boys will be challenging and rewarding and teach you the value of patience, kindness and building relationships with children.

You will have to decide whether to pursue a PhD in history or become a high-school teacher. You will choose the latter for a number of reasons: because you can have a bit more impact on the lives of young people and because you will still be able to research and write about history.

Your first teaching job will be in a challenging urban school with uneven parental involvement, in Rochester, New York. The area is deprived and ethnically diverse. Later, you will teach in Webster, a more suburban, middle-class area. You will be keen to keep working in Rochester, but you will be offered a job in Webster first. Teaching there will be a better gift than you imagine. You were a product of Webster schools and teach in the same school you attended as a child.

In Rochester, your greatest achievement will be providing stability for one cohort of students who had 12 different teachers in five months before you arrived. You will be able to create a working classroom environment and students will learn effectively because you will change the culture of that classroom. In Webster, you will work as part of the team to carry out a similar cultural change, but on a larger scale.

Always remember that excellence in teaching comes one student at a time, one class at a time, one day at a time. I know that sounds trite, but excellence is the cumulative impact of daily interactions with students. Any advice I offer you comes from a mountain of mistakes, which all teachers must be encouraged to make. But the reality of teaching, the challenge and joy of our craft, is that it is built on trust and relationships. Build trust each day with each student.

To that end, we need to love and learn two things: our students and our content.