What can a high schooler do to prepare for a software engineering job?

1) Learn to Code 2) Do your own projects 3) Contribute to open source software 4) Pick up an algorithms book and study it. I personally used this one and found it very concise but still compact. http://www.amazon.com/Algorithms-Sanjoy-Dasgupta/dp/0073523402/ref=sr_1_4?ie=UTF8&qid=1387699320&sr=8-4&keywords=algorithms 5) Make sure you are enjoying it. Otherwise, maybe it's not for you, which is totally okay

Dive into programming now. You have access to all the resources you'll need for a career in the future at your finger tips right now (there's mountains of documentation available online since everyone loves to talk about their work). All you need to start is an idea and language to give the idea matter. If you don't like the style of the language, there's a few thousand more to choose from (most languages simply re-iterate the same logic using different grammar). P.S. question everything