Somewhat generic advice: Find a good local bookstore (way easier in cities, particularly those with universities) and start flipping through relevant books unti

Somewhat generic advice: Find a good local bookstore (way easier in cities, particularly those with universities) and start flipping through relevant books until you find one that speaks in language you understand -- there's really no substitute for this, since your background (maths/physics/compsci) and learning style are super-relevant. I'm a really big fan of MIT press textbooks; they consistently are of excellent quality and authorship (and no, I didn't go to MIT). They're not cheap, but they're significantly cheaper than taking a course.