Versatile
An effective logo works across a variety of media and applications. For this reason, logos should be designed in vector format, to ensure that they scale to any size.
Ask yourself, is your logo still effective if it is printed…
In one color?
In reverse color (i.e. light logo on dark background)?
The size of a postage stamp?
As large as a billboard?
One way to create a versatile logo is to begin designing in black and white. This allows you to focus on the concept and shape, rather than color, which is subjective in nature. Also keep in mind printing costs: the more colors you use, the more expensive it will be for the business over the long term.