Most people are loyal to their mediocre accountants. And switching accountants feels like a pain. The only times that they are going to be especially susceptible to marketing from a new accountant are:
A good accountant should point out the screw ups that mediocre accountants are prey to. She should appeal to entrepreneurs, and she should be ramping up her marketing at key times in the financial calendar.
When are your prospects going to be receptive? What will they be doing at that time? Where?
You need to find the answers to those questions. When you do, it will dramatically change your pitch.