I haven't touched a BASIC dialect since QBasic, but general a good way to learn a language with a lot of infrastructure behind it is to pick up a book (yes, a printed book) that people who use that language approve of, read it, then write some toy but not-entirely-trivial programs with it. I like little roguelikes and OpenGL toys for that purpose, but pick a program you've written before because the point is to figure out the best way to write it in your new language, not to tackle both a new language and a new problem.
Brings back memories. My first assignment of my first programming class in college (and I'm a novice now--at that time I didn't really even know what computer code was) I made a street craps game. Still the most fun program I've ever written....write some toy but not-entirely-trivial programs with it.