The preparation of any test depends on in which area you are. Many online institutions offer teacher in your area. They provide a techer who is actually an old test taker. The question is "The person having experience of just taking test is a good teacher or an institution having an experience along the development and changing tracks of the test (GMAT, GRE, SAT)". Reference http//www.gmat.com.pk http//www.gre.com.pk