Young people form quick impressions about their teachers, so the way you look, act and generally carry yourself is of enormous importance - especially when you meet a new class. Teachers should be genuine models of the behaviour and conduct that they expect from their classes.
It's a regrettable fact of life, but many pupils encounter teachers who are often grumpy and tired. It may not always be easy, but you should try to present as positive and as cheerful a face as you can: your pupils take their cue from you and so how you set the tone of a session can happen early on. I'm not suggesting that you should walk around all day like some deranged Cheshire cat, but it is important to look and sound as upbeat as you possibly can.
It's also important that you uphold the same sorts of standards that you expect from your pupils. That means, for example, returning marked work punctually and ensuring that you honour commitments you have made about activities or special arrangements. Young people look to adults that they can trust and who are reliable.
Take care looking after your resources and equipment. It's difficult to demand neatness and tidiness from pupils if your own teaching space is a shambles and you're scrabbling around trying to locate your own stuff.
And never underestimate the importance of how you look. I would never presume to give advice on dress sense (I can hear ex-colleagues spluttering as I write) but the golden rules are to conform to the dress code of your school and to be clean and neat at all costs - just wait for the comments from your class when you fail to meet these standards.
Jon Berry is a senior lecturer in the school of education at Hertfordshire University.