Make your staff feel an important part of the team. You should have business cards, and possibly stationery, memo pads, and other items printed in the staff person's name.
Encourage a pleasant telephone manner. After all, when a client prospect calls in, it is the voice that creates the first impression.
Insist on a neat, professional appearance. Dressing for success should apply to staff. When clients or prospects come in to your office, they meet your staff first. Your staff, their appearance, and the appearance of your office are all extensions of you!
Be professional! Encourage professionalism in your staff.