I receive many requests from high school students who wish to do research with me. The document here has two goals:
Concerning Point 1: I am philosophically opposed to high school students doing research. You should be learning more of the fundamentals at this point, including math at an insightful level (no, a 5 in AP Calculus, or for that matter most "enrichment" courses, do NOT count), history, literature, politics and so on.
Now, regarding Point 2, there are two types of students who want to do research: Type I does research because they believe research experience will help them in applying to college. Type II does research more out of intellectual curiosity. I am not implying that either type is superior to the other, but my remaining comments are for Type II.
Research is a creative activity. And in turn, creativity is fostered by constantly sifting the material through your mind. Ideally, it results in your occasionally waking in the middle of the night with a "Eureka!" moment.
Accordingly, ideally you should not be involved in another significant academic activity simultaneously with research. Summers are thus best, and if you are taking summer school while doing research, you are not really doing research.
For the same reason, during your research time, don't hestitate to speak up. If you don't understand something, of course try first to resolve it on your own, but if it is still unclear, don't be shy about asking!
Similarly, if you have an idea as to how to improve a method, or regarding another aspect of the research that might be worth investigating, say so! Sometimes you, as an "outsider," may actually have better ideas.
And finally, make sure you're being challenged. Your research adviser may have underestimated what you are capable of. Don't be afraid to ask for more responsibility.