I am having trouble with the ASVAB I've studied used flash cards, read, etc. everyday took practice tests and?

still on my practice tests my score is the same. The only thing I score excellent in is paragraph comprehension the rest I score poor in. Is their a trick to making a good grade on this thing? I have my bachelors degree and I want to get into the officer marine corp program basically I have to score good on my ASVAB to get into that. Is their any test taking tricks or some trick to help me make a better grade on this thing? The book I have been studying I got at a university bookstore and it has practice tests, etc. and I have studied this thing for 4 months. Are their any tricks to making a good grade on this thing?