My favourite time management system was simply three columns: SEP, MP, & MEH, and a graveyard for 'done' (however that happened). Every task/thing was on a post-it note and put into a column, with height within a column to indicate importance.
MP was My Problem. SEP was Someone Else's Problem. And MEH was exactly that: maybe, eventually, hopefully. The motto along the bottom reads: Divide and Conquer. The goal is to deal with whatever was MP ASAP - realizing that most things aren't actually my problem, or once I do my little part, it's not my problem. Or really, no one but me cares about this thing but me, so it doesn't matter if it stays undone until I can prioritize it.
A key point is that every task not in the graveyard is something you still care about being completed. So tasks under SEP while not MP, are things I want to keep track of. Between (or on the line between) SEP and MP are tasks that I can't complete myself but that I am responsible for ensuring get done, by minions perhaps.
I can't really describe the satisfaction, of an empty MP column (I never managed it) but the growing pile of dead tasks in the graveyard feels good.