Typical situation with Google Reader: not only does your feed list grow like the Nokia snake in short order, but your tags aka folders list will as well. Sooner or later you will have to limit your time spent in the app because it will be impossible to process everything no matter what you do.
Once you’ve accepted this reality (it will take a certain amount of time :>), it starts to make sense to prioritize tags in the display list. This is useful for quickly glancing over key categories without scrolling through your whole list, which helps keep in-app time spent lower and simultaneously keep the mind at ease. “Phew, I did not miss that massively important blog post, another crisis averted!” type thing.
I have found using the format of “+tag” accomplishes this goal when alphabetic sorting is used and is pleasing to the eye, no doubt thanks to Google recently rewiring my brain according to their plus-sized masterplan.
Note that I have everything sorted alphabetically, because the overhead accompanying manual drag-n-drop sorting probably doesn’t assist with the original goal of spending less time with the app.