I've found http://www.ccs.neu.edu/home/matthias/HtDP2e/ http://www.ccs.neu.edu/home/matthias/HtDP2e/ to be the best resource to drill the "code as data" mindset

I've found http://www.ccs.neu.edu/home/matthias/HtDP2e/ http://www.ccs.neu.edu/home/matthias/HtDP2e/ to be the best resource to drill the "code as data" mindset necessary for Lisp programming. And I would recommend going through as many exercises in http://sarabander.github.io/sicp/ http://sarabander.github.io/sicp/ as possible using the Racket IDE: https://docs.racket-lang.org/sicp-manual/index.html https://docs.racket-lang.org/sicp-manual/index.html