Don't you find that most trips have a ton of stuff in common though? Pajamas, contact case/solution, loofah, spare phone battery, ear plugs, phone charger & battery charger, reusable water bottle, etc. always go with me on every trip.
IMO the stuff that always goes is the stuff that I tend to forget, exactly because there's nothing unique about this trip that would make me remember it. If I'm going to the beach I know I need my swimsuit and beach shirts because I can walk through my activities and think about what I need for each one. But I'm likely to forget pajamas because I'm not thinking about "go to bed every night" as an activity to plan for.
Checklists FTW. Nobody above me has mentioned Atul Gawande’s book ‘The Checklist Manifesto’ so, just on the off-chance you’re not aware of it, there you go. I loved it. (Gawande is the doctor who implemented the checklist in this article.)
I have a packing crate for socks, one for underwear, one for causalwear and pants.
Then I just need to think how many nights I'll be gone to pick how much goes into each.
(Also reduces space in my carry on so I have room for conference schwag on the return leg)
The other thing is just bring less stuff. A lot of people are amazed by how little I carry and I don't consider myself extreme. Consider what you really need as opposed to want.
(Then again maybe I'm not travelling enough for your advice to apply...)
I agree on the bringing less stuff front. I've slowly pared down a lot of what I bring, and just stop in a drugstore to pick up if I forgot some minor thing.