Contact the SSAT Board. They will know which tutors are most qualified to help you with SSAT prep. Contact information can be found on the SSAT website.
Check with the school that is requiring you to take the SSAT. Ask the administration if they can refer you to someone who can help you prepare for the test.
Consider buying a SSAT prep DVD. These are usually a less costly option than paying for a private tutor.
Try preparing for the SSAT through Tutor.com. They have online libraries to browse and an introductory offer for a reasonable fee for private one on one tutoring.
Check the credentials of the tutoring facility you choose before paying any fees. Ask them about the tutor's education, experience and references. Be sure to check all qualifications.
Set goals with your tutor and work to meet them. Goals help focus your tutor time and make it more productive.