<p>The [AMC12</a> Archives](<a href=“http://www.unl.edu/amc/e-exams/e6-amc12/archive12.shtml]AMC12”>http://www.unl.edu/amc/e-exams/e6-amc12/archive12.shtml) should be a good site to explore; You can also order past
exams from UNL (they are about a buck each and totally worth it).</p>
<p>You may find [the</a> AoPS forum](<a href=“http://www.artofproblemsolving.com/Forum/index.php?f=133]the”>http://www.artofproblemsolving.com/Forum/index.php?f=133) and the books from AoPS to be helpful :)</p>