? Don't wear all black. You'll look as though you're disappearing into a hole. This often throws women into a panic, as we love the slimming properties of black, particularly when TV will probably make you look slightly heavier than you are in real life. Black trousers or skirt will normally be fine as a filmed interview will generally concentrate on your top half, but do go for a colour on top if you can.
? Don't wear all white. It makes TV lights bounce back and you'll look as though you just descended from the heavens on a cloud.
? Don't wear anything with a very small pattern such as pin-stripes, tweed or polka dots. Again, it has a strange effect on TV lights known as strobing. Men should avoid pinstripe shirts ? bring a change of clothes if you're not sure.
? No visible logos of companies or brands (watch out for this particularly on sportswear) as this may be regarded as advertising. You may be asked to change if a logo is too obvious.
? Avoid buying a new outfit the day before and acting as if you're going to a job interview. If you feel too stiff and formal in your clothes this will affect how you express yourself.
? If you can't decide what to wear, bring a change of clothes ? plenty of people do and it can be a good idea if your original choice turns out to be unsuitable.
? Ask if there are any colours you should avoid wearing. This can happen if they clash with the set, or if an effect called ChromaKey is to be used ? this is the effect which is used as the basis of some special effects, where a particular colour is replaced by pictures. The usual colours affected by this are green and blue (this is why it's commonly known as blue screen effects). So if you were in a studio where this effect was being used and you happened to be wearing a blue tie, you could look as if you had a big hole in the middle of your body, which will probably not enhance your corporate image.
? Above all, ensure that however you look is congruent with how you want to come across ? if your message is sober and serious, dress appropriately. Likewise, if your message is fun and frivolous you can probably leave the navy suit at home. Some TV professionals reckon that wearing pastel colours can make you look younger, but you may not necessarily want to look younger, especially if you're appearing in an expert role.
It's worthwhile bearing these guidelines in mind any time you meet a member of the media, even if it's non-visual interview such as radio or print. How you look will still have an impact on how you are perceived, so make sure you give the impression you intend to on all levels.
And in case you were wondering, it is true that television can make you look as if you're a few pounds heavier than you are in real life. It's all to do with the fact that a TV picture is made up of a series of horizontal lines, and other technical reasons I won't bore you with.
Suffice to say, when you meet people who regularly appear on TV, they often look much smaller and slimmer than you might expect ? this is because many TV presenters (especially female ones) decide to keep as skinny as possible in order to look regular size on the box.
Now, how you regard this is up to you. I'm not telling you this so you can all rush out and join Weight Watchers. It's just something else about the process to be aware of and take into consideration. You don't have to look a particular way or be a particular weight to appear on TV, but it will help your over-all performance if you are happy in your own skin, whatever size that may be.
Joanne Mallon is a life coach, journalist and TV Producer who has coached hundreds of people through TV interviews.
This is an extract from The Beginner's Guide to TV Interviews, the ebook available from http://www.MediaLifeCoach.com. Visit the site to find out more about our coaching programs and free newsletters.
You can contact Joanne by emailing joanne@medialifecoach.com