What separates the good student teacher from a bad one? The staffroom can be an intimidating place and student teachers need to be aware of the sensitive arena they are stepping into. Teachers can be very territorial, especially about mugs and chairs. Is that chaise-longue you've fallen asleep on the exclusive domain of the head of languages?
"A mistake about which chair to sit in can set you off on a disastrous teaching practice," says Tom Megahy, headteacher at River Leen school, Nottingham. "But nobody tells you things like that, until it actually happens."
"Teachers ascribe huge significance to seemingly trivial things," says Geoff Brookes, deputy head at Cefn Hengoed comprehensive in Swansea. "For example, park in the head's space and you will never recover."
"You need to take a bit of time to understand the culture of an organisation," says Mr Megahy. "There is no such thing as the typical school. As teachers, we can learn a lot from student teachers. Sadly, some schools don't see it like that."
His brother was placed at one school, some years back, where student teachers were banned from the staffroom. Fortunately, this is a rare thing.
More than half the new entrants to teaching are 25 or older, and more student teachers are coming from industry. Sometimes they have difficulty adjusting to the more humble nature of teaching life.
"They can be insensitive in the staffroom, talking about their high salaries and exotic holidays," says James Williams, dean of education and PGCE programme leader at Sussex University. "One actually said to me 'I'm teaching because I want to, not for the money - my pension is bigger than your salary'. This isn't the right attitude - a bit of humility is needed in the staffroom."
He remembers a trainee whom he sent to a school in south-west London. "She decided the school didn't have good enough resources so, without consulting anyone, she ordered hundreds of pounds' worth of science textbooks. Only when the head of science got the invoices did the matter come to light. She didn't last the rest of the course."
Sara Bubb, PGCE lecturer at the University of London's Institute of Education, believes that, generally, trainees are superb and their rough edges can be ironed out. "Coming from industry, the notion of spending a couple of hundred pounds is nothing, but to a school it's a lot," she says.
"One student teacher I dealt with was very good except for his erratic time-keeping - he didn't have a watch. He had some hippy-ish disagreement with constraints of time. This was obviously going to be a problem: if you're three minutes late collecting the class from the playground, that can be very irritating for other members of staff."
Another had an enitirely different problem. "He had BO, and wore the same clothes day in, day out. Everyone was dropping hints, which he didn't get, so it was up to me to have a word."
A cautious dress code is advisable. "Student teachers need to dress conservatively," says James Williams. "Bare midriffs and facial piercings are not advised, especially for women, as it encourages competition with the pupils."
This is more of an issue in secondary schools than primary. "The culture in secondary school is different: the school is larger, the age range bigger, the gender difference increasing."
Student teachers need to be alert at all times. Tom Megahy recalls on his first day of teaching practice at his first school in Sheffield: "The teacher reprimanded a boy in the Year 6 group for tossing exercise books at pupils instead of just handing them out. He hadn't noticed that the boy only had one arm. The other had been burnt off in an accident with a pylon."
Ambition without foresight can have terrible consequences, as Joan Fenton, head at Dyce primary school in Aberdeen, remembers: "One student had baked a fish for a science class and put the skeleton on display on the Friday, prior to a long weekend. We returned on Tuesday to an almighty smell which permeated throughout the school."
Ultimately, the best student teachers are the ones who are the most aware of their surroundings, and the most self-aware. "Being relaxed in a placement and comfortable with colleagues doesn't mean you can drop standards of dress, attendance, punctuality or professionalism," says Sean McPartlin, deputy head at St Margaret's Academy in Livingston.
"Students are under scrutiny and can't afford to present as 'quirky', there is plenty of time to develop your persona once you are qualified and in post. Don't be a robot, but don't come across as a loose cannon."
* Go into the staffroom, join in chats and generally blend in. "Don't sit with other students away from body of staff," advises Joan Fenton. "Don't hog conversation, criticise other schools, your tutors, pupils in your class, even if invited to - we know how bad they are."
* Respect confidentiality. "Teachers and teaching assistants need to let off steam somewhere," says Mick Brookes, head of Sherwood junior school in Nottinghamshire and former president of the National Association of Head Teachers, "so beware of staffroom negativity and taking it at face value".
* Figure out staffroom routines. Bring your own mug to begin with and offer to pay for coffee.
* Attend after-school meetings if you can. "Not because it looks good, but because it gives you an insight into how schools really work and helps you make a better contribution," says Janet Johnson, a mentor to student teachers at St Fisher RC high school, Harrogate.
* Use your down time wisely. Don't sit reading the paper - offer help.
* Buy sweet things to share. Fruit is good but biscuits and cakes are more likely to win friends and influence colleagues.
* Arrive and leave just on time. You should come and go when the majority of staff do.
* Don't forget to inform the school when you're off sick - someone has to pick up the pieces and take the lesson.
* Walk out of the school on the first morning declaring that the quality of teaching is not good enough, as a student of Tom Megahy's did. The school may well disassociate itself from the university PGCE programme altogether.