WHEN TO START PLANNING:
SAT, ACT, Subject Tests, AP and Duel Credit, Transcript Building, Volunteering, Skipping a Grade...
the trick is to start early. Don't wait until high school; a great time to start planning is in the 4th grade. There are a lot of great resources online and through the schools if you know where to look. See the video for 3rd-7th graders and parents: What elementary students can do to prepare for the test.