100 years ago the knowledge a standard high school student brings isn't that much. They're probably well educated, but will not have deep knowledge of valuable things yet to be invented. They can't attempt to patent a steam engine or corner the market with internal combustion or with electricity - these things are already there.
They are not well educated enough to attempt to invent any truly new technology. Transistors and semiconductors are complicated. They also require 40 odd years of improvements to chemical engineering and materials science to even get to the point of making them. A high school student won't know how to reproduce the big advancements in aeronautics, in mechanical engineering, or electrical engineering.
The best bet in my opinion is to try and use the fact they are reasonably well educated to get employment in one of the victors of WWI (100 years ago would put you after the end of that of course), and take part in any post war booms they can. If we ignore your 10 year deadline, a reasonably well educated person should be able to get their money into semi safe areas. Assuming you arrive in 1919;
- Don't invest in Germany until the hyper-inflation is over, if at all
- The Great Depression will kick off in 1929. Don't be in debt, pull money out of risky things in advance, possibly attempt to bet against the market.
- Invest in telecoms if you can, especially in America.
- Try and get involved in American defense contracting.
Those are just my initial ideas, but none of them will see big pay offs until well after your 10 year deadline.
A specific person with personal knowledge might do better. If you know how to make really good washing machines from not much you could probably corner that side of light industry, or similar. But again, this is down to the person at least in my opinion.