Q: Do you sometimes plan the structure of a song in advance? I'm torn between free-form-writing as it comes and the clarity that comes with a fixed form. (And also it's much easier to work towards "let's do an AABA tune".)
A: it's mostly impossible to know exactly what the form will need until you start writing it, however, the song will offer you clues. sometimes the initial idea will very clearly be a 'chorus', and sometimes you get a clear picture of what it will need. other times, the first idea will be like the title at the beginning of the A of AABA. it's really all about taking the initial idea and 'diagnosing it', with the most important question simply being 'is this the beginning or not the beginning'