Here is my top 10 list of essential travel items I have narrowed it down to after all the traveling I've done.
1. Universal adapter plug. In this technological era, we all can't live without our phones or laptops
2. Sarongs. This multi-use cloth is amazingly useful. Turn it into a scarf, dress, pajamas, pillow manchester (duno where those airplane pillows have been) shawl for modesty covering, or as an beach towel.
3. Zip-lock plastic bags. A few in different sizes even. Great for compartmentalizing the dirty & clean, wet from dry and protecting your luggage from messy leaky toiletries.
4. Quick dry tshirt. Again, a multi-use clothing. For the gym/sweaty activities, sleeping in, beach to snow. Wash it at night, and its ready to go the next day. Bonus: no ironing required.
6. Travel laundry line. Clothes dry faster this way. Bonus: hang a sarong on it for extra privacy at hostels
7. Small, foldable day bag. Extra bag for day trips where you can chuck around your drink bottle, maps, rain jacket, camera, etc. Bonus round: Shopped too much. Whip this out for extra carry-on luggage.
8. Bug spray. They's just... everywhere
9. Pack of Tissues. Common sense and yet I often forget to bring these...then I spill something, there's something sticky on my seat, and I realise...no tissues.) Bonus: use as toilet paper (you'll be surprised how many places charge for toilet paper or just have none.)
10. Hat. Sunny or cold, pack a hat...keeps the glare away, keeps you warm, and keeps your hair away from your face. Also, get a hat that you won't care if you accidentally leave it behind. Get a cheapy.