If you are planning to hire a graphic designer, collecting some images that appeal to you beforehand can speed up the creative process. Just the practice of looking at design styles and colors may help you articulate what qualities you are looking for in your new image.
Color is an important and dynamic ingredient in any design. Keep in mind the possibility that your new image may be copied or faxed in grayscale or black and white at some point.
Take a moment to consider all the ways your graphic image will be used and consider its integrity at many different sizes and resolutions. A logo designed for a business card may also need to look good sized for a letterhead, a report cover, a sign or a web site.