I've finally figured out a way to use Astrid with the Getting Things Done (GTD) concept of projects, being sequences of actions. One thing you're supposed to do in GTD is to review your projects list to make sure that each project has a current action, to keep it moving. I've always had a Projects list in Astrid, but now I'm using Astrid's "subtasks" feature to assign other tasks to projects.
They're not quite real subtasks, though, just indented from the others which makes them look subordinate. Also, you have to specifically enable the feature and select drag & drop ordering for your list on Astrid for it to work at all. Still, it was a missing piece of the puzzle for me, and I'm glad I sorted it out. Now I have a Projects list with all my ongoing projects on it, plus individual context lists like Shopping, Home and Errands to sort tasks into their necessary groups. It's working pretty well for me so far.
Mokalus of Borg
PS - I'm going to look at some other organisation methods soon.
PPS - Just to see if there's anything better for me than GTD.