<p>Why do you want to re-take? Unless math is your "specialty," 720 is probably OK.</p>
<p>Anyway, just practice with a good book for half an hour to an hour per day for about a month before the test. That's always worked for me when I wanted an 800. (BTW, I did score 800 on the IIC.)</p>
<p>No don't use Barron's... it teaches you stuff that's not even on test... use stuff that's actually close to the test... Sparknotes is slightly easier and Princeton review is good... only use Barron's if you're a really advanced student in Math.</p>
<p>Barron's book is the best. Do all the tests and understand all how to do them. They are actually harder problems than you will see in the actual test but if you know Barron's all problems you have a pretty good chance to get 800. I teach these courses so I know from the actual students' scores</p>