After working through examples from "Introduction to Programming," and feeling like you've mastered the basics,
I recommend diving into some source code and learning how others do it.
I cut my teeth as a high school student on a source listing of the EDU-200 BASIC interpreter.
The code wasn't always the best, but it was a great learning experience to see how someone else cut up
a complex problem and distilled it into PAL8.
-Bill