Reddit reviews Form in Tonal Music: An Introduction to Analysis, Second Edition

A lot of it is just stuff I've learned in conversations with people more experienced than me, but in terms of books, I used Green's Form in Tonal Music in a theory class, and it was pretty solid!

1. Score study. After you finish the great orchestration books, the primary source of further study is always the works of great composers.
   
   
2. Form in Tonal Music by Douglass Green is good for this purpose, although it's not comprehensive. Perhaps what you're really looking for is something like the Anthology for Musical Analysis by Burkhart & Rothstein.
   
   Sorry about the prices of those books on form. That's pretty typical for forms & analysis books since they're primarily text books.