If you've got yourself an interview with a leading graduate recruiter, it's not enough to have a sparkling CV and all the key facts about the company and the role you're applying for at your fingertips. You'll also need to know how to conduct yourself correctly to ensure you make a good impression - by William

The clothing you choose is going to have a considerable impact on the impression you make on the interviewer - and the outcome of the interview. People form impressions of others within a few seconds of meeting them, so the significance of what you wear is immense.

William advises that for an interview at a City firm, you should assume that business dress is required and wear a suit. If, however, you're being interviewed for a role in a profession where business suits are not normally worn, for example, PR or media, then you can dress more casually. But, William vehemently adds, "never wear jeans". Belts should match the colour of your shoes, and if you're wearing a suit, both should be black as "brown remains for casual wear." And your shoes should be well polished and in good condition - for example, the laces should look neat and not frayed at the ends.

What to do with your hair is a concern for both men and women, as how it looks can say a lot about your personality. For William, the key point to be underlined for both genders is that your hair should be "neat and off the collar".

Men should "avoid using so much hair product that you look flammable". Excessive gel or wax can make you look not only unprofessional but also juvenile - in particular, "steer clear of wet-look gel; we are not thirteen", comments William.

William advises women that their hair should be "brushed and under control". If you have long hair, it should be "tied back or better still, cut!"

Your greeting is likely to be your first face-to-face contact with your interviewer, so it's vital that you get it right. William says you should aim for a "firm not limp, but equally not too firm" handshake. You should only use your right hand, leaving your left hand dormant by your side. Eye contact is essential throughout the interview process, so remember to look the interviewer in the eye when shaking hands. You should introduce yourself by saying your name clearly, followed by "How do you do?"

In most interviews you'll almost certainly be seated on a chair facing the interviewer. You want to position yourself so that you look attentive but can be comfortable for a lengthy period of time. William's advice is to "sit on the edge of the chair, or right at the back". A common error is to sit in the middle, which will cause the back to slouch and completely ruin the image of yourself you want to portray.

"Always let the interviewer speak, and they should let you speak too" advises William. Put yourself in the interviewer's shoes and you will realise that being cut off mid-sentence can be rude and annoying, especially if you're about to say something important. Also, your interruption might be unnecessary as you could be about to ask something the interviewer was about to mention. Be patient, listen conscientiously to everything the interviewer says and save any questions you have for after the interviewer has finished talking. Also, remember that you can always ask any unanswered questions at the end of the interview when the interviewer should ask you if you have any final queries. "Give the interviewer respect and you will get respect back", is the key principle for William.

The biggest mistake you can make is to assume the interview is over and make the first move towards leaving. Instead, William says, you should wait for a cue - "when the interview is over, the interviewer will make it clear".You should then "thank them for their time, proffer your hand and leave as quickly as possible, but without rushing or tripping over". William emphasises that the end of the interview is just as important as any other part, and perhaps more so because how you leave will be the last memory the interviewer will have of you - so make sure you conduct yourself appropriately.

Now that William's briefed you on correct behaviour, it's over to The Gateway for the misdemeanours to avoid - just remember everything your mum told you when you were little, and you'll be fine!

Don't be late: Your interviewees are busy people making time to meet you, so it's inconsiderate to hold up their schedule. And you want to have a few minutes to collect your thoughts once you arrive in the building rather than arriving out of breath and stressed. If an event beyond your control delays you, call your potential employer as soon as possible to let them know what's going on.

*Don't be rude: *This principle applies not just to the interviewers but to anyone you meet on the day, including doormen, receptionists, the person who shows you to the room, junior staff, or other candidates. We're sure they don't deserve it and you don't know who's reporting back on you!

Don't forget names: Don't forget the names of your interviewees - make a mental note of them and use when appropriate. If you're invited for a second interview, make sure you know who you spoke to the first time round.

Don't be confrontational: Your interviewers might well ask you some difficult questions, then challenge your answers. It's not a personal attack, so stay calm and measured at all times while standing up for your point of view where appropriate - you need to show you can stay cool under pressure!

Don't lie: This one's a big one. Never lie on your CV, or when asked a question about your experience at interview. And it's also not a good idea to be less than honest when asked whether you'd definitely take a position offered to you - admittedly you're not signing a binding contract at this point, but saying yes when you're not sure will not endear you to graduate recruiters at the employer you're applying to, and word can spread quickly through an industry.