that's easy: using your brain. self-study. Wikipedia. Lots of other stuff on the Internet. a library. experimentation. exploration. play. try/fail. reading. getting mentors. building things. taking things apart. teaming up with others on collaborative projects, both locally and geo-distributed. acquiring friends with similar interests and learning from one another.

all much faster, cheaper, and more flexible, with less makework, and a pace and curriculum that is more attuned to your unique needs, desires, abilities and circumstances. oh and less likelihood you'll start a career in debt.

works for all fields equally well? of course not. but for some, it rocks.

also, i have a startup in this space so I'm making a bet on the validity and value of this kind of approach.