I am not an educator so please take note of my position in the Cheap Seats.
The first thing I would do is change from paper text books to eReaders. We can pay over a hundred dollars per book. Why do that when you can buy a licensed copy for virtually nothing. Get a math guy to write the perfect algebra book. Pay him something huge, like $500,000 for the rights to it. Then forever more, every student in the United States will have free access to an electronic copy of that book. Algebra doesn't change. Many of the English books that students read are currently free online. History books can be kept current. Every book they will ever need is neatly stored in a single eReader that cost a couple of hundred dollars. A wireless system like the one Kindle uses can download assignments and such as well. No more tens of thousands of dollars each year for books. No more heavy backpacks or "I left my books at school or home." If its on the eReader, its online as well.
The second thing I would do is incorporate some sort of gaming activity in learning. How can we not be paying attention to how the minds of our kids get wrapped around gaming. I am certain that my 16 year old son could learn a foreign language in a week if he thought it would get him a trophy or an achievement online. There is something about the way the games get into the children's heads that motivates them to learn. They go home and play 21st century games after a day of 17th century schooling.
The third thing I would do is add to after school activities. More sports. More plays. More community service. Idle kids are kids open to less than optimal activity paths.
The fourth thing I would do is teach societal and introspective material. Why not teach the 12 steps of a recovery program? Why not teach yoga?
Finally, I would make school last year round with several smaller breaks. High schools would start and end 2 hours later (in accordance with overwhelming evidence about circadian cycles).
My goal would be to make out educational system number one in the world. No more Top 50.