Clothes and manners do not make the man; but, when he is made, they greatly improve his appearance.

-Henry Ward Beecher


Not long ago, it was commonplace for a man to don a suit every morning before he came in to the office. No matter his position, title, or income, if he was in an office, he was dapper.

In our time, however, there are so many varying levels of dress that it is easy to get lost in what means what? How is executive casual different from mainstream casual? Which one is closer to traditional business attire?

Sylvie di Giusto, founder of Executive Image Consulting, works with executives looking to improve how they present themselves and professionals hoping to impress their clients and bosses. In her new book "The Image of Leadership," she breaks down the five levels of dress code that she uses with her clients.

We've represented them below, and included di Giusto's insight into how to make your clothes work for you in the office:

If you're not sure which level is most appropriate for your work environment, the basic rule of thumb is "the more you deal with a client's money, the more traditional and conservative you should be dressed," di Giusto says.

That means that people in finance, law, and accounting, for example, should stick to traditional business attire, and those in creative industries, like entertainment and advertising, can dress flexibly within the casual levels.

If you're a member of the board or meeting with a member of the board, boardroom attire is most appropriate — regardless of the size of the company.