I just found a neat post over on Photoday where the author wrestles with all the various ways of dealing with David Allen’s Getting Things Done system. I empathize, as there are as many ways to implement the system both manually or via a computer as there are pages in the original book. Still, it’s always interesting to read about someone else’s efforts.
To answer the question about next actions, though, they are simply next actions – they aren’t today’s next actions, so if you don’t get them done today just move them to tomorrow. You shouldn’t be making new next actions unless you’ve finished the old one anyway.
As for the rest of it…it’s kind of like sex – once you get started each successive step becomes pretty obvious.