I use calibre too. any new book gets the TBR tag and I have a virtual library based on that. When my kindle gets low on books (low being under 100), I'll browse the virtual library and pick the next series/book that has the earliest date.
That way I'm reading stuff by date added instead of "what do I feel like". I've eliminated the "feels" from my reading and haven't had a slump in almost 4 years now. It's obviously not for everyone
