Never underestimate the amount of underwear and socks you will need:
It’s already difficult enough to find undies you like at home in your size, imagine abroad! It’s not like underwear takes that much room anyway… You can also use packing cubes to help keep it tightly packed and easy to find as it’s all in a single place.
Solid as a rock:
Most toiletries (the exception being antiperspirant!) that you normally carry in liquid/gel format can now be found in a light, compact, NON-LIQUID version: shampoo, conditioner, hand, laundry & body soap, even shaving foam/ gel! (Travelon sells all of those and more!) As compact as can be (2.75″ x 2″ x 0.75″), those are 3-1-1 compliant & carry-on friendly (for those who only carry hand luggage); a MUST to avoid unfortunate leaks and unpleasant security check at the airport!
Otherwise, a good old bar of soap (instead of fancy shower gel) will last longer, can’t really leak and potentially doubles as laundry soap, even shampoo (if you don’t have needy hair)!
Segregate Clean and Dirty…
… unless you want your entire luggage to smell bad! An inexpensive nylon stuff sack will do the trick. It’s also useful to carry damp clothes so the rest of your luggage won’t get humid. Considering the room it takes, bringing 1 or 2 is nothing! Buy one that’s rugged enough to be machine washed; it will need to be thoroughly cleaned every once in a while to remove odors.
Don’t throw in the towel!
I love my long, thick, fluffy towel. But it takes the size of 3 days of clothing in a backpack! If you lodge beachside or plan on living in accommodation that provides towels, don’t bring it. But if you must pack one:
1) Use a “travel” towel – much smaller and dries quickly so you can wash it often
2) Bring it long enough to properly cover yourself, especially if you live in a family that you connected with through hospitality websites (like BeWelcome or Staydu); it will keep you decent if you need to walk out of the bathroom! (Also applies to hostels with communal shower facilities.)
Being plus-size, I bought two MSR PackTowl Personal Towel, size XXL at Mountain Equipment Co-op (MEC) and got some Velcro sewn on one end of each towel, so I can use them together or separately. Attached, it’s long enough to wrap around the body and goes all the way down to the knees. Separated, it does the trick for drying hair, wring clothes that are just washed and other not too extensive drying duties! This towel dries in about 20-30 minutes compared to hours (if not days!) for regular towels. (Once folded, my 2 XXL towels are about 11″ long x 8″ wide x 2″ thick.) Anti-microbial treated to diminish that “dirty old towel” smell.