Documenting everything ruthlessly (meeting summaries, action items, personal knowledge, TODOs, passing thoughts ala things I want to discuss with peers, etc) in a centralized and easily searchable/cross-linkable/organizable fashion.
Build this doc repo as well as the TODO component within it for absolutely minimal mental overhead. In fact, optimize for minimal mental overhead in all things, and ability to reenter/pick up where you left off effectively "on autopilot." This (low mental overhead, reentrency) applies to things like email triage as well.
I realize this is both very terse and very open ended, but it's really the crux of my ability to deal with exponential levels of randomization, complexity, and parallel tasks. If there's any "Secret sauce" this doesn't contain, it's the need to adjust your systems/organization/methods to whatever is "natural" for you (this perhaps goes hand in hand with low mental overhead and reentrency, even the process must be low-overhead and easily 'reentrent', for instance, preparing for forgetting where I put something, I should know my own tendencies for where I'd look such that I buid my organization upfront that I'd readily find it again.)
I'll cap this with one more meta item before I turn this into an essay: Retrospect. regularly ask yourself "how are things? how is what I'm doing? can it be improved? has anything gone wrong/should I be paying attention to anything I'm not? are there any questions I'm not asking?"
