In short the best method is the following: (1) interview a few brokers who are familiar with your area and that have had success and (2) importantly one with whom you have some real chemistry. Conversly the same will be true for any solid broker ; for in the process, they will be mentally interviewing you as well, with the aim of their ability to take on a home and in turn do a solid job for you.
My suggestion, if you are looking for excellent results, choose an excellent agent with a proven track history.
I am a local Realtor familiar with the area. Actually I grew up in Bay Shore! You can call me at 631-680-0079 if you have any questions. I am happy to recommend Realtors in the area and would be pleased to share names and phone numbers with you! Please call at your earliest convience.
Best of luck to you.