What should one do as a high schooler to best contribute to the world's utility? I've done a lot of reading, but what is the definitive answer? Or as close to definitive as possible.

You mean which subjects? It's a tough question, which I've been trying to break down a bit here, partly because I'm thinking about going back to retake high school subjects myself.

Actually, at school I don't think the answer's that difficult, since options are generally still quite generic at school, so universities don't necessarily require you to have studied the subject you intend to do there at school. Assuming you're reasonably competent, you probably can't go too wrong with maths, which is a sufficient prerequisite* for almost everything, physics, which is a sufficient prequisite for almost everything practical, and biology or chemistry, which are sufficient for almost everything else.

*sufficient as in accepted as a qualification, not necessarily the only qualification you'll need - you'll prob need at least two of the 'sufficient' ones.

I don't know what is your school system, but I recommend you to study science.

You should be focusing on increasing your future potential. I'd say your efforts should be mostly academic for now.

As far as your courses go, I'll add my voice to the "study science and math" chorus. I'd add that a statistics course is likely to be especially useful. Studies indicate that taking a stats class improves your reasoning abilities, and stats is essential in many scientific and business contexts. You should also take an economics course (microecon preferably). This should teach you some important things about how society is organized, give you some general tools for thinking about a wide class of problems, and teach you something about pursuing your goals in a rational way. (Internalizing the notion of an opportunity cost, and not treating them differently from ordinary costs, is important to thinking about things in a rational way.)

Where do you live? If you live in the US, many states allow you to take college courses while in high school for dual credit (fulfil high school requirements and college requirements at the same time). Some of them will even pay for this. If you have the opportunity to do this, I would recommend that you use it to the max. Try to fulfil your writing requirements by taking philosophy courses. And I'd recommend taking a logic course from your math or philosophy department.

Other than that, you should try to get into the best university that you can, so that you are in a position to do as much good as possible. If you live in the US, I can give you some more advice here.

Again, thank you all for your posts. This website is amazing. I'm still a novice in this utilitarian business, but I'm learning the lingo slowly and surely. I'm in the United States, and I do plan to take (or have taken) all the courses mentioned. I hope to attend a top-tier instution (although I'm not sure as far as careers go, that's a Utilitarian quandary I've yet to figure out). Also, I've already begun spreading Utilitarian thoughts, to notably keen interest

I think you're making a good move by talking to people at felicifia. Good to network and interact with smart and dedicated folks.

Another place you can interact with smart and interesting folks is the blog Less Wrong, at www.lesswrong.com. There are a lot of examples of clear thinking there, and a lot of things that challenge conventional ways of thinking. I'd consider checking it out in your spare time, if you want something interesting to read. Click on "Sequences" and read the series "Mysterious Answers to Mysterious Questions" and "How to Actually Change Your Mind". A lot of that stuff comes from other sources (philosophers and cognitive scientists), but I think it is useful to know.

They also have a monthly "Open Thread" on Less Wrong. You might consider asking your question there (many people will be sympathetic, since many there are utilitarians/consequentialists).

Here is some more concrete advice about doing well on the college front:
1) Nail your SATs/ACTs. If you don't already know you're going to absolutely kill it (99 percentile), I'd consider a) taking a test prep course, b) buying test prep books and studying. A useful tool for learning vocabulary is a program free program called "Anki", available here: http://ichi2.net/anki/. The cost of doing well here is vanishingly small compared to the expected benefits of going to a good college (not just for what you'll learn in classes, but in terms of who you'll network with).
2) I'd also make sure you have good study habits. A lot of people learn stuff only to forget it later. (At least for the big stuff, try not to just learn it for the test.) Make sure you have a good system for keeping long term notes on important subjects. A good program for this is FreeMind (downloadable for free here: http://freemind.sourceforge.net/wiki/in ... /Main_Page). Mindmaps are a useful way to condense a lot of general information (works for me anyway).
3) Get involved in some extracurriculars. Example: If there is some scientific subject you're interested in, you might look into volunteering or trying to get a job at a university lab. You'd learn some useful things and meet people it would be good for you to know.

I hope this helps. I'd be happy to answer any more questions you might have. You are facing a lot of important decisions and I want to make sure you get things right.

I support the idea of studying maths/science. These are prerequisites for many high-paying courses.
I agree that studying economics shares some of the principles of utilitarianism. Perhaps philosophy would also explain utilitarianism and its competitors. However, neither of these suggestions weighs heavily in my considerations.

In my opinion, what's important is getting a good final year mark. It's all about the VCE. Or SATs, A-Levels, or whatever they're called in your country. They're the single most important consideration in the life of a high-school student. Here's how I suggest you choose subjects to give yourself the best chance of good marks:
1. Study what you're good at.
2. Pursue subjects you enjoy so that you are capable of studying them at home for hours, week after week.
3. When exams are tough, top marks go to students who have best conceptual understanding. When, on the other hand, exams are simple top marks go to students who make the fewest silly mistakes. If, like me, you're a clever although sometimes careless student, pick hard subjects.