Read a bunch of Paul Graham.
While in high school: treat it like a day job. Work on your interests, and develop your skills.
Try to avoid video games. Avoid alcohol.
In college: Don't focus on classes. Focus on people, and focus on ideas. Your goal in college should be to meet a few people cleverer than you are (settle for as clever if necessary). Introduce yourself to people, and don't get locked into the group that forms in the first week. If you enjoy a professor's class, go to their office hours and chat. Remember, understanding is not something you finish- it is the shore of an island. The more you know, the more you are immediately able to learn- and so if you've got what's in the curriculum find one what's on the edge of the curriculum.
It seems to me very likely that the best way to reduce x-risk is to work on other issues you're better at and then donate the money you're able to earn there. "If you want to create wealth (in the narrow technical sense of not starving) then you should be especially skeptical about any plan that centers on things you like doing. That is where your idea of what's valuable is least likely to coincide with other people's." --Paul Graham
Math seems like a pretty foundational field for a lot of things. I recommend becoming a competent programmer in at least one language (preferably something like Ruby, but you can probably make more money freelancing with something like Perl).
Don't be afraid to seize value. If there are classes you find interesting that you aren't in, go to them. If there are professors you want to talk to about things, go to their office hours, or email them, even if you aren't in their class or their department.
Thanks, I particularly found the whole "just go to classes you feel like" bit interesting. Slash looking forward to it.
So for most people directly working on existential risk is inefficient. How can you tell if it would be efficient?
Most people in the US with internet connections who are reading this site will at some point in their lives graduate high school. I haven't yet, and it seems like what I do afterwards will have a pretty big effect on the rest of my life.*
Given that, I think I should ask for some advice.
Generally,
Any advice? Anything you wish you knew? Disagreement with the premise? (If you disagree, please explain what to do anyway.)
More specific to the site,
Any advice for high schoolers with a rationalist and singularitarian bent? Who are probably looking at going to college?
Anything particularly effective for working against existential risk?
Any fields particularly useful for rationalists to know?
Any fields in which rationalists would be particularly helpful?
This is intended to be a pretty general reference for life advice for the young ones among us. With a college selection bent, probably. If you're in high school and have a specific situation that you want help with/advice for, please reply to this post with that. I think that a most people have specific skills/background they could leverage, so a one-size-fits all approach seems to be somewhat simplistic.
*I understand that I can always change plans later, but there are many many things that seem to require some level of commitment, like college.
Edit:
As Unnamed pointed out, also look at this article about undergraduate course selection.