The magic of packing lists
After years of traveling and several mid-trip-emergency-runs to Target or worse, searching all over Hong Kong for a bikini that fit my western hips, I have learned many packing lessons. Over the past few years I have cultivated a system that works very well for me and has (mostly) prevented spending a small fortune for items I already own but have been forgotten at home.

My secret weapon for packing incredibly efficiently: insanely detailed lists.
My lists are crazy detailed and are a process to build, but they not only prevent me from forgetting items, they also prevent me from overpacking. I now find myself able to take a carry-on sized case for long trips and have space inside to bring back souvenirs and trinkets.
Here's my packing list process:
Plan (and write out) all my outfits based on trip itinerary
Split each outfit into categories: Tops, bottoms, underwear, etc.
Use the categorized list to pack my suitcase
Planning the outfits is the longest and hardest part of the process. I usually start this 1-2 weeks out from my trip, but sometimes I start it even earlier for more complex trips. I start by thinking about the things I will be doing and what I might want to wear. I doodle these ideas in my journal. Once I start to form a more solid picture of my schedule and what I want to wear, I write all of this out, including as many details as possible, in a format similar to this:
Monday | Travel day/Check In to Hotel/Casual dinner
Travel - Leggings, running shoes, loose tunic top, backpack
Casual dinner - skinny jeans, white cami, black tank top blouse, feather earrings, Under Armour nude sneakers
Tuesday | Beach day, all day
Pineapple bikini, green shorts, white tank, black flip flops
Bring in bag: jean shorts, t-shirt, hoodie, UA sneakers
Once my outfit plan is complete I start my detailed packing list with all my items broken up by category.
For this I start a new sheet with categories in columns: tops, bottoms, accessories, underwear, toiletries. I then run through each outfit and drop each item into the right category. I don't include my travel outfit to this as I will be wearing it. So my outfits above would end up looking like this on my list:
Tops
black tank top blouse
white tank top
t-shirt (any)
Bottoms
skinny jeans
green shorts
jean shorts
Underwear
white cami
nude bra
pineapple bikini
sports bra
no-show socks x 2
Accessories
feather earrings
I draft my outfit plan and packing list on a small pad of paper. I staple or clip it to the month of my trip in my planner. I refer to my outfit plan throughout the trip to remind myself of what I wanted to wear. Getting ready during a trip can be overwhelming. Pre-planning my outfits help simplify the experience and saves me precious time!
Erin Condren has a simple travel dashboard which I use for shorter trips, including all my work trips. Anything longer and I feel like my detailed list system is better.