One of the key questions any leader will ask themselves about an employee regardless of what that employee's role might be is: "Do I feel comfortable putting this individual in front of a customer or client or business partner?". If the answer is no, then you have all the makings of a career killer.
Often the "no" is a result of an individual's poor hygiene or poor manners. At any rate, it is absolutely key that your hygiene is beyond reproach if you are going to get ahead. Having great hygiene will not accelerate your career. Having poor hygiene will stall it out completely though. It is that important.
So what sort of things are we looking for here? Certainly, you should be clean and that means taking a shower or a bath daily, washing your hair and keeping your hands and finger nails clean. I once was working with a female manager who was in the washroom at the same time as one of her up and coming employees. The up and coming employee failed to wash her hands after using the toilet and...that was the end of that promising career. My client said, she just could not look at her the same way again, let alone shake her hand!
It is also key that you don't over do the perfume or deodorant because you don't want to be known as the "Aqua Velva Man" or the "Tigress Women". What we are looking for here is clean first and then if necessary subtle perfume that is almost hard to discern. Keep in mind that you own nose will quickly become acclimatized to what ever scent you are wearing. Don't fall into the trap of believing that just because you can't smell it any longer, no one else can either.
Brushing your teeth is a good thing as well. Very little is as distracting in a tight meeting room as someone with dirty teeth and bad breath. Please - do yourself a favor and brush your teeth regularly. Oddly enough, in spite of claims to the contrary, breath mints and chewing gum rarely do an adequate job here. (Just as an aside, chewing gum should be banned from the workplace. Do yourself a career favor and don't chew gum in the office. Seriously!) On the matter of oral hygiene, never floss your teeth in public. Certainly not at your desk and if absolutely necessary, you can do it in the restroom but ideally wait until there is no one else present. Everyone has to floss at some time but no one likes to see another person doing it - ever.
Another area where I find people can get caught is in the cleanliness of their clothing. This can be a tricky one, especially if you are wearing a suit because the jacket may in fact be hung up on a hanger all day and never really seem to need dry cleaning...but it does. A rule of thumb is that shirts (or blouses) and socks only get worn one day before being cleaned. Pants, slacks, skirts etc., are a bit tougher but count on no more than 8-10 wearings between dry cleaning. Ties can usually wait until they are soiled or require pressing. Of course it goes without saying that any soiled garment gets washed right away. There is no such thing as an "okay" stain.
Just to reemphasize, the idea here is not to be fashionable or noticeable. It is actually to be invisible when it comes to hygiene. You don't want people to notice that you are clean - it is the price of entry to an accelerated career.