[jyl]

I've taken GMAT and LSAT, also SAT.

There are some tricks to taking these tests, have to do w/ time management as much as subject matter.

You'd be wise to at least get some prep books, take the sample tests, get a sense of how you will do and get familiar w/ the test format.

Then how much study you need to do will depend on how high a score you want, which depends on what school you are trying to get into.