Your Shoes: Place shower caps over the bottoms of your shoes, that way you can lay them safely over your clothes without having to worry about stains.
Travel Checklist: Create a travel checklist; not only to not forget something while packing, but also to remind yourself of important tasks that need to be completed before you leave (i.e. set thermostat, refill prescriptions, talk to the one person who will water your plants, etc.).
Inflatable travel pillows Better than the stuffed (You can make their size fit your needs) and they help prevent neck pain allowing for comfortable sleep (especially on long flights) and from accidentally using you neighbors shoulder as a pillow.
A water bottle Bring along a water bottle, that way you don’t contaminate by buying plastic water bottles, and simply re-fill (Mostly all hotels have drinkable water refilling possibilities).
Noise-cancelling headphones They not only allow for uninterrupted sleep, but also send out a memo to your chatty neighbor, that you are not in the mood. Place your earplugs underneath the headphones & you are sure to have some peace & quiet.
Mix items in the bags: If you are traveling with your husband/wife, boy/girlfriend, or best friend… Always mix items in the bags. Day and evening wear, underclothes and footwear for each of you in both bags, that way you each have something to wear if any of the bags gets lost.
Bubble Wrap — small bubbles — for any breakable items you might buy along the way. I am sure it’s saved more than one treasure I have gotten home safely and it takes up no space at all.
Old Clothes This is specially useful for shopaholics… Bring old clothes to use in your trip (Trousers, shirts, etc.), things that you don’t mind getting rid of. At the end of the trip you can throw the old clothes and refill your bags with souvenirs.
Perfume or Cologne Bring your favorite perfume or cologne along without the worry or mess of a broken bottle. Spritz a generous amount on a few cotton balls & store them in a medicine bottle. Just rub on neck & pressure points when needed.
Hand Sanitizer Travel sized hand sanitizer. With so many travelers touching nearly everything in sight, it is nice to have this handy to make sure you bypass all of those sickly germs.
Roll your clothes: When packing your suitcase, rolling your clothes not only saves space, but prevents wrinkles as well.
Sleep masks They are nice when you want to go to sleep & the lights are still on, or if you are in need of a daytime cat nap.
Carry on bag: Always bring a carry-on bag with your overnight essentials, just in case your luggage gets lost or you miss a flight & end up overnight at the airport while your luggage is on its way to your destination.
Stash Extra Cash: Cash is king around the world. To cover your ass in an emergency, make sure to stash some in a few different places. I recommend at least a couple hundred dollars worth. If you lose your wallet, your card stops working, or the ATMs run out of money, you’ll be glad you did. Some spots include socks, under shoe inserts, a toiletry bag, around the frame of a backpack, even sewn behind a patch on your bag.
Back Everything up: Keep both digital and physical copies of your passport, visas, driver’s license, birth certificate, health insurance card, serial numbers, and important phone numbers ready to go in case of an emergency. Backup your files & photos on an external hard drive as well as online with software like Backblaze.
Plastic bags: Bring some extra plastic bags. Either to put dirty clothes or to place your clean clothes in (For instance traveling in the rainy season with the luggage on the roof of car or microbus).