Make a check list. That always brings me peace when I got a bigbshoot the next day.
Yea, that definitely helps, but I always seem to leave a few gimmies off of it and then am like, "ok, I packed my laptop... but did I remember the power cable?"
Trello list. A card for every suitcase/bag. That way not only is it packed, but you know where it is.
Credit cards and passport- I'm sure you already thought of this, but I usually am scrambling to call the banks to let them know I'm using my cards in different countries. Was surprised Thailand was ok but China wasn't for my Chase cards.