I’ve been following Bruno Dias’ Making Interactive Fiction series at sub-Q Magazine since it started, and the most recent installment discusses branching structure in an interesting way. It’s especially useful to read in conjunction with one of my favourite CoG blog posts, End Game and Victory Design.
The series is well worth a look for anyone interested in writing IF (or just thinking about the nuts and bolts behind it). I find the Scenes article particularly useful for helping me think consciously about the functions of scenes and how they fit into the wider game.