Learning new languages is just one dimension, learn new algorithms, learn new computational problems, learn high level APIs, learn low level stuff, learn how machines work at the bare metal level, learn how operating systems work.<p>Make things, make toys, make tools, make big projects, make oneliners.<p>Write new things, rewrite old things, fix shitty code you find on github, fix shitty code you wrote. fix bugs you find, increase performance of slow things.<p>tl;dr Get better by doing.