Every business and professional practice MUST be in the public eye. They won't benefit from your services, and you won't make any money. So, marketing is a necessity.
Advertising is one form of marketing, but it's terribly expensive.
Contact 5 past customers or referral sources to thank them for their business and ask them to evaluate the quality of your service. Let them know they are the most important part of your research and development program. Re-do your business cards, brochures or letterhead. Up-date your slogans, be certain your use of colors, textures and headlines is appropriate and represents precisely the image you want to convey. Hire a graphic designer.